CBSE > Class 12 > Chemistry | CBSE Board | Homework Help

Ask questions which are clear, concise and easy to understand.

Ask Question

What is electromotive force of a cell?

Posted by Atul Yadav 4 years, 2 months ago

1 answers

Tannu Rao 4 years, 2 months ago

Work done to move a unit test charge inside a cell from negative terminal to positive terminal in absence of its internal resistance or when the cell is open circuited is called electromotive force of a cell.

0Thank You

ANSWER

a solution containing 18g of non volatile solute at 200g of h2o freezes at 272.07 k.find the molecular mass of the solute?

Posted by Prajakta Chhetri 4 years, 2 months ago

CBSE > Class 12 > Chemistry

2 answers

Adity Gupta 4 years, 2 months ago

Ess question me kh ki value nhi hai question is in complete

2Thank You

Ishant Dixit 4 years, 2 months ago

Number of mass/total mass multiply by 100 kar do

1Thank You

ANSWER

If any one has has question bank of class 12 of all chapters please send me

Posted by Kushagra Singh 4 years, 2 months ago

CBSE > Class 12 > Chemistry

1 answers

Adity Gupta 4 years, 2 months ago

No sorry

0Thank You

ANSWER

Name the binding force in. Metallic solid

Posted by Rashi Shetty 4 years, 2 months ago

CBSE > Class 12 > Chemistry

2 answers

Tannu Rao 4 years, 2 months ago

Metallic bonding

1Thank You

Adity Gupta 4 years, 2 months ago

Force that holds atoms together in metallic substance

0Thank You

ANSWER

What is conductivity????

Posted by Akhilesh Chauhan 4 years, 2 months ago

CBSE > Class 12 > Chemistry

4 answers

Siddhant Singh 4 years, 2 months ago

Ability to conduct electricity

0Thank You

Vishal Singh 4 years, 2 months ago

Conductivity is reciprocal of resistivity

0Thank You

Sujit Yadav 4 years, 2 months ago

Property of any body to let pass the electric current through it

0Thank You

Sumit Kumar 4 years, 2 months ago

Inverse of resistivity

0Thank You

ANSWER

What type of interaction hold the molecules together in a polar molecular solid?

Posted by Th Henba 4 years, 2 months ago

CBSE > Class 12 > Chemistry

5 answers

Vishal Singh 4 years, 2 months ago

Dipole dipole interactions

0Thank You

Adity Gupta 4 years, 2 months ago

Dipole interaction

0Thank You

Akhilesh Chauhan 4 years, 2 months ago

Dipole dipole

0Thank You

Pratyush Sahoo 4 years, 2 months ago

Dipole dipole interaction

1Thank You

Ricky_Romeo _Raaz 4 years, 2 months ago

Electromagnetic force

0Thank You

ANSWER

Comapre the acidity of phenol and ethanol with diagram

Posted by Ashish Singh 4 years, 2 months ago

CBSE > Class 12 > Chemistry

1 answers

Kabita Sharma 4 years, 2 months ago

Phenol +water ----->Phenoxide ion + hydronium ion Alcohol + NaNH2 -----> sodium ethoxide + NH3 Alcohol+ Na-----> Sodium alcoxide + H2 Here you can observe that phenols readily for hydronium ions (H30+)which is more acidic than H+ ion liberation.

0Thank You

ANSWER

Preeti dabral plz tell me . Are you a teacher ? I hope so because you answered many of the questions asked by students .

Posted by Nishant Pandey 4 years, 2 months ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

Accept tin and zinc which another metal can be used to protect iron from rusting????

Posted by Nishant Pandey 4 years, 2 months ago

CBSE > Class 12 > Chemistry

1 answers

Akhilesh Chauhan 4 years, 2 months ago

Zinc as it is also used in coating for prevention of rusting....

1Thank You

ANSWER

Arrange

Posted by Sanjana Silpa Saha 4 years, 2 months ago

CBSE > Class 12 > Chemistry

3 answers

Siddhant Singh 4 years, 2 months ago

Kya krna h arange ?

0Thank You

Nishant Pandey 4 years, 2 months ago

?????????????????

1Thank You

Nishant Pandey 4 years, 2 months ago

What arrange

1Thank You

ANSWER

N2 gas is bubbled through water at 293 k how many millimoles of N2 gas would dissolved in 1 litre of water? Assume that N2 exerts a partial pressure of 0.987 bar. Given that Henry's law constant for N2 at 293 k is 76.48 k bar.

Posted by Tushar Hooda 4 years, 2 months ago

CBSE > Class 12 > Chemistry

1 answers

Badal Barasiya 4 years, 2 months ago

According to Henry's law, p N 2 =K H .X N 2 ⇒x N 2 = 76800 0.987 =1.29×10 −5 Moles of water in 1L= 18 1000 =55.56 Let us take the moles of nitrogen as n Total moles =n+55.56 ∴ x N 2 = n+55.56 n =1.29×10 −5 ⇒n(1−1.29×10 −5 )−55.56×1.29×10 −5 =0 ⇒n=0.7×10 −3 =0.7 milimoles

2Thank You

ANSWER

Explain the cleansing actionof soap

Posted by Prince Shah 4 years, 2 months ago

CBSE > Class 12 > Chemistry

1 answers

Preeti Dabral 4 years, 2 months ago

When soap is dissolved in water, its hydrophobic ends attach themselves to dirt and remove it from the cloth. First, the molecules of soap arrange themselves in micelle formation and trap the dirt at the centre of the cluster. These micelles remain suspended in water like particles in a colloidal solution.

1Thank You

ANSWER

What is the reason for the charge on sol particles

Posted by Akash Yadav 4 years, 2 months ago

CBSE > Class 12 > Chemistry

1 answers

Preeti Dabral 4 years, 2 months ago

Sol particles develops electrical charges due to dissociation of surface molecules. Sols may be either positively or negatively charged . This charge can be balanced by oppositely charged ions in the sol.

0Thank You

ANSWER

i Assertion: The presence of equal and similar charges on colloidal particlesis largely responsible in providing stability to the colloidal solution. Reason: The repulsive forces between charged particles having the same charge prevent them from aggregating and provide stability. ii. Assertion: The first layer is mobile in Helmholtz electrical double layer. Reason: The potential difference between the fixed layer and the diffused layer of opposite charges is called zeta potential. ii. Assertion: The sol particle in colloid has a charge. Reason: The charge in sol is due to electron capture by sol particles during the electrodispersion of metals. iv. Assertion: Methylene blue sol is a negatively charged sol. Reason: When KI solution is added to AgNO3 solution, positively charged sol formed. v. Assertion: If FeC13 is added to an excess of hot water, a positively charged sol of hydrated ferric oxide is formed. Reason: When ferric chloride is added to NaOH a negatively charged sol is obtained with adsorption of OH- ions.

Posted by Pranjal Sharma 4 years, 2 months ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

Colloidal particles always carry an electric charge. The nature of this charge is the same on all the particles in a given colloidal solution and may be either positive or negative. The charge on the sol particles is due to one or more reasons, viz., due to electron capture by sol particles during electrodispersion of metals. When two or more ions are present in the dispersion medium, preferential adsorption of the ion common to the colloidal particle usually takes place. When silver nitrate solution is added to the potassium iodide solution, the precipitated silver iodide adsorbs iodide ions from the dispersion medium, and negatively charged colloidal solution results. acquired a positive or a negative charge by selective adsorption on the surface of a colloidal particle The combination of the two layers of opposite charges around the colloidal particle is called Helmholtz electrical double layer. The presence of equal and similar charges on colloidal particles is largely responsible for providing stability to the colloidal solution. In these questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices. Assertion and reason both are correct statements and reason is correct explanation for assertion Assertion and reason both are correct statements but reason is not correct explanation for assertion Assertion is correct statement and reason is wrong statement Assertion is wrong statement but reason is correct statement Assertion: The presence of equal and similar charges on colloidal particles is largely responsible in providing stability to the colloidal solution. Reason: The repulsive forces between charged particles having the same charge prevent them from aggregating and provide stability. Assertion: The first layer is mobile in Helmholtz electrical double layer. Reason: The potential difference between the fixed layer and the diffused layer of opposite charges is called zeta potential. Assertion: The sol particle in colloid has a charge. Reason: The charge in sol is due to electron capture by sol particles during the electrodispersion of metals. Assertion: Methylene blue sol is a negatively charged sol. Reason: When KI solution is added to AgNO3 solution, positively charged sol formed. Assertion: If FeCl3 is added to an excess of hot water, a positively charged sol of hydrated ferric oxide is formed. Reason: When ferric chloride is added to NaOH a negatively charged sol is obtained with adsorption of OH- ions.

Posted by Pranjal Sharma 4 years, 2 months ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

Nucleophilic addition reaction of aldehydes and ketones

Posted by Arpusee Deka 4 years, 2 months ago

CBSE > Class 12 > Chemistry

1 answers

Sia ? 4 years, 2 months ago

Unlike the situation in a nucleophilic substitution reaction, when a nucleophile attacks an aldehyde or ketone carbon there is no leaving group – the incoming nucleophile simply ‘pushes’ the electrons in the pi bond up to the oxygen.

2Thank You

ANSWER

What is the difference between isotropy and anisotropy??

Posted by Nishant Pandey 4 years, 2 months ago

CBSE > Class 12 > Chemistry

2 answers

Preeti Dabral 4 years, 2 months ago

<th scope="col">Characteristics</th> <th scope="col">Isotropic</th> <th scope="col">Anisotropic</th>

Properties	Direction independent	Direction-dependent
Refractive index	Only one	More than one
Chemical bonding	Consistent	Uncertain
Uses	Lenses	Polarizers
Light passes through it	No	Yes
Velocity of light	Same in all directions	Different
Appearance	Dark	Light
Double refraction	No	Yes
Example	Glass	Wood

2Thank You

Nishant Pandey 4 years, 2 months ago

Thank u very much

1Thank You

ANSWER

Assertion: higher alcohols are produced in industries by sugar fermentation Reason: higher alcohols are produced in industries by hydration of petroleum-derived alkenes

Posted by Elizabeth Ram 4 years, 2 months ago

CBSE > Class 12 > Chemistry

1 answers

Sia ? 4 years, 2 months ago

assertion and reason are correct

0Thank You

ANSWER

Properties of alcohal

Posted by Radha Krishna Nayak 4 years, 2 months ago

CBSE > Class 12 > Chemistry

2 answers

Sia ? 4 years, 2 months ago

Physical Properties of Alcohol

1. The Boiling Point of Alcohols - Alcohols generally have higher boiling points in comparison to other hydrocarbons having equal molecular masses. This is due to the presence of intermolecular hydrogen bonding between hydroxyl groups of alcohol molecules. In general, the boiling point of alcohols increases with an increase in the number of carbon atoms in the aliphatic carbon chain. On the other hand, the boiling point decreases with an increase in branching in aliphatic carbon chains the Van der Waals forces decreases with a decrease in surface area. Thus primary alcohols have a higher boiling point.

2. Solubility of Alcohols - The solubility of alcohol in water is governed by the hydroxyl group present. The hydroxyl group in alcohol is involved in the formation of intermolecular hydrogen bonding. Thus, hydrogen bonds are formed between water and alcohol molecules which make alcohol soluble in water. However, the alkyl group attached to the hydroxyl group is hydrophobic in nature. Thus, the solubility of alcohol decreases with the increase in the size of the alkyl group.

3. The Acidity of Alcohols - Alcohols react with active metals such as sodium, potassium etc. to form the corresponding alkoxide. These reactions of alcohols indicate their acidic nature. The acidic nature of alcohol is due to the polarity of –OH bond. The acidity of alcohols decreases when an electron-donating group is attached to the hydroxyl group as it increases the electron density on the oxygen atom. Thus, primary alcohols are generally more acidic than secondary and tertiary alcohols. Due to the presence of unshared electrons on the oxygen atom, alcohols act as Bronsted bases too.

Chemical Properties of Alcohols

Alcohols exhibit a wide range of spontaneous chemical reactions due to the cleavage of the C-O bond and O-H bond. Some prominent chemical reactions of alcohols are:

1. Oxidation of Alcohol

Alcohols undergo oxidation in the presence of an oxidizing agent to produce aldehydes and ketones which upon further oxidation give carboxylic acids.

Alcohols: Physical and Chemical Properties

2. Dehydration of Alcohol

Upon treatment with protic acids, alcohols undergo dehydration (removal of a molecule of water) to form alkenes. Dehydration of alcohol

1Thank You

Radha Krishna Nayak 4 years ago

Thanks

1Thank You

ANSWER

Write the name of element and symbol of group number 15,16,17 and 18 and the elements of 3d and 4d series of d block

Posted by Yash Kumar 4 years, 2 months ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

To all my juniors this is my last message to you all, I know that sometimes we all feel anxious but don't let that affect your preparation.Please prepare well and write your exams well I wish you all a great future ahead and a great score too.May all of you get 95%+ with your hardwork and dedication.

Posted by Shreya Singh 4 years, 2 months ago

CBSE > Class 12 > Chemistry

5 answers

Snehil J@@T 4 years, 2 months ago

M to vese hi puch rha tha kyonki m ab 12th m hu

0Thank You

Snehil J@@T 4 years, 2 months ago

No esi baat nhi h

0Thank You

Shreya Singh 4 years, 2 months ago

I don't know but my gut feeling says that you are trying to judge me but I was sure that I would cross 96% with ease of exams were there.

1Thank You

Shreya Singh 4 years, 2 months ago

Nahi Telangana board mein 11th class ka bhi board exam hota hai to mere 11th board mein jitne marks aaye the utne hi mujhe 12th mein de diya gya

1Thank You

Snehil J@@T 4 years, 2 months ago

Shreya apke paper hue the koe

0Thank You

ANSWER

Hey guys my 12th results came today... I'm from Telangana board and I got 94% in my boards so hopefully it's my last day on this app. All the best to all of my juniors...keep studying,keep hustling. Good bye.

Posted by Shreya Singh 4 years, 2 months ago

CBSE > Class 12 > Chemistry

5 answers

Shreya Singh 4 years, 2 months ago

Thanks Tec Om may you score even better than me

3Thank You

Tec Om 4 years, 2 months ago

all the best for your future may god help you to find your own way

2Thank You

Shreya Singh 4 years, 2 months ago

No I don't use insta and any other social media

1Thank You

Snehil J@@T 4 years, 2 months ago

Did you have Instagram id

1Thank You

Snehil J@@T 4 years, 2 months ago

Congratulations shreya for your cute result like you

5Thank You

ANSWER

What do you mean by isotropy?

Posted by Atharva Verma 4 years, 2 months ago

CBSE > Class 12 > Chemistry

5 answers

Preeti Dabral 4 years, 2 months ago

Isotropic materials are materials whose properties remain the same when tested in different directions. Isotropic materials differ from anisotropic materials, which display varying properties when tested in different directions. Common isotropic materials include glass, plastics, and metals.

1Thank You

Atharva Verma 4 years, 2 months ago

Thanks ?

0Thank You

Tec Om 4 years, 2 months ago

the property of substance in which properties like refractive index, electrical conductivity, thermal expansion etc have the same values in all directions is called isotropy

1Thank You

Raushan Kumar 4 years, 2 months ago

Isotropy means that something having identical values of property in all directions.

0Thank You

Sonali Das 4 years, 2 months ago

isotropi means having identical values of a property in all directions.

1Thank You

ANSWER

How does preparation of haloalkane takes place 1.) from alcohol and 2.) From hydrocarbon

Posted by Shreeya ? 4 years, 2 months ago

CBSE > Class 12 > Chemistry

2 answers

Ranger King 4 years, 2 months ago

2Thank You

?⚡Her?️⚡? 4 years, 2 months ago

1) by reacting with X2/thionyl chloride/PCl5
2) by passing H2

2Thank You

ANSWER

11 gm of naoh is dissolved in water and 500ml solution is prepared if density of solution is 1.1gm/ml then find out mass%

Posted by Ankita Ranga 4 years, 2 months ago

CBSE > Class 12 > Chemistry

2 answers

Tec Om 4 years, 2 months ago

MASS of solute is 11gm density 1.1gm/ml by using density formula d=m/v 1.1=m/500 m=550gm mass%=mass of solute /mass of solution *100 mass%=11/550*100 mass%=2%

1Thank You

Tec Om 4 years, 2 months ago

<pref>weight of solute is 11 gm D=M/V 1.1=M/500 M=550 MASS %=mass of solute/mass of solution *100 MASS%=11/550*100 =2% </pref>

1Thank You

ANSWER

Meaning of amorphous

Posted by Yogesh Kumar K.S 4 years, 2 months ago

CBSE > Class 12 > Chemistry

2 answers

Preeti Dabral 4 years, 2 months ago

Amorphous solid, any noncrystalline solid in which the atoms and molecules are not organized in a definite lattice pattern. Such solids include glass, plastic, and gel.

0Thank You

Sher Singh 4 years, 2 months ago

The type of solids which have no regular arrangement and have very short range ordered.they have completely random shape like rubber, plastic,glass etc.

1Thank You

ANSWER

Does derivation of NERNST equation come in boards? Is it important to know its derivation for boards ?

Posted by Shrestha Pal 4 years, 2 months ago

CBSE > Class 12 > Chemistry

3 answers

Vishal Singh 4 years, 2 months ago

Nhi ayegi 50 percent syllabus toh mcqs he h so not possible

0Thank You

Shrestha Pal 4 years, 2 months ago

Yeah....it's better to do so...but will the derivation come or only numericals based on that formula are important ?

1Thank You

Technical Jiva 4 years, 2 months ago

Yes it can come in boards but not so important No one knows which questions will come in boards So I prefer to learn and memorize everything given in NCERT.

1Thank You

ANSWER

How much no. Of numericals ask on board exam

Posted by Mohit Sanatani 4 years, 2 months ago

CBSE > Class 12 > Chemistry

2 answers

Sree Sowmya Dantuluri 4 years, 2 months ago

1 question of 5marks 2 questions of 3 marks 2 questionsof 2marks

1Thank You

Sree Sowmya Dantuluri 4 years, 2 months ago

Only of 15 marks

1Thank You

ANSWER

How we can find association and disassociation number of hydrochloric acid.

Posted by Mohit Sirohi 4 years, 2 months ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

Explain , why aquatic animals are more comfortable in a winter than in summer.?

Posted by Suman Sultana 4 years, 2 months ago

CBSE > Class 12 > Chemistry

4 answers

Preeti Dabral 4 years, 2 months ago

Increase in temperature decreases the solubility of oxygen in the water. The amount of oxygen dissolved in water decreases at a higher temperature. As a result, it becomes more difficult to breathe less dissolved oxygen. Hence, the aquatic species are not comfortable in warm water.

0Thank You

Raushan Kumar 4 years, 2 months ago

Because in winter ,the temperature is low so solubility is higher . Aqiatic animals needs more dissolved oxygen for breathing.

0Thank You

Abhishek Singh 4 years, 2 months ago

Because

0Thank You

Mohit Sanatani 4 years, 2 months ago

Search in google

1Thank You

ANSWER