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

Only molality is temperature independent. Others are temperature dependent because there values depend upon volume and volume is temprature dependent.

1Thank You

ANSWER

What happens when lanthanum is heated with sulphur

Posted by Aditya Sharma 6 years ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

What is safe selective catalysis .

Posted by Rajnish Kumar 6 years ago

CBSE > Class 12 > Chemistry

1 answers

Yogita Ingle 6 years ago

A catalytic reaction which depends upon the pore structure of the catalyst and on the size of the reactant and the product molecules is called shape-selective catalysis. For example, catalysis by zeolites is a shape-selective catalysis. The pore size present in the zeolites ranges from 260-740 pm. Thus, molecules having a pore size more than this cannot enter the zeolite and undergo the reaction.

2Thank You

ANSWER

Name tha metal used as reducing agent for MnO2

Posted by Radha Gupta 6 years ago

CBSE > Class 12 > Chemistry

1 answers

Yash Surya 6 years ago

Carbon

0Thank You

ANSWER

What is henery law

Posted by Kp Singh Yadav 6 years ago

CBSE > Class 12 > Chemistry

2 answers

Gaurav Seth 6 years ago

Henry’s Law establishes aquantitative relation betweenpressure and solubility of a gasin a solvent.
This law is for gas-liquid solution.
According to the law at a constant temperature, thesolubility of a gas in a liquid is directly proportional to thepressure of the gas.
It can also be stated as - The partial pressure of the gas in vapour phase (p) is proportional to the mole fraction of the gas (x) in the solution.
Mathematically,

p = K_H x where K_H= Henry’s law constant.

0Thank You

Radha Gupta 6 years ago

Ghghh

0Thank You

ANSWER

Propanone is treated with dil. Ba(OH)2 ???

Posted by Yuvraj Singh 6 years ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

Please send me the blueprint of chemistry

Posted by Pragati Chaudhary 6 years ago

CBSE > Class 12 > Chemistry

2 answers

Ankur Dahiya 6 years ago

Yes, he is right. Man Har told u correctly.

0Thank You

Man Har 6 years ago

Solution,electrochemistry,chemical kinetics, surface chemistry is of 23 marks General principle and processes of isolation of elements ,P-block elements,D-and F-block elements ,Co-ordination compounds is of 19 marks Ful part 2 (all organic) of chemistry is of 28 marks

2Thank You

ANSWER

At 333k and 1 atm of N2O4 is 50% dissociated into NO2 then Kp is

Posted by Ns H 6 years ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

Although phenoxide ion has more number of resonating structures than carboxylate ion, carboxylic acid is a stronger acid than phenol. Give two reasons

Posted by Tushar Verma 6 years ago

CBSE > Class 12 > Chemistry

1 answers

Abhay Mehta 6 years ago

Because in carboxylate negative charge is more dispersed over two oxygen atom whereas in phenoxide only on one oxygen atom

0Thank You

ANSWER

Name the unit formed by the attachment of base 1' position of sugar in a nucleoside.

Posted by Vidyanshu Sinha 6 years ago

CBSE > Class 12 > Chemistry

3 answers

Ankur Dahiya 6 years ago

This question is in sampe paper published by cbse under free sample papers section. And cbse provided answers also. Answer is Nucleotide.

1Thank You

Ankur Dahiya 6 years ago

Nucleotide

2Thank You

Yogita Ingle 6 years ago

A nucleoside is one of the structural components or building blocks of DNA or RNA. A nucleotide consists of a base (one of the four bases: adenine, thymine, guanine, and cytosine) and a molecule of sugar and phosphoric acid. They are formed by the attachment of a base to 1’ position of sugar in a nucleoside.

1Thank You

ANSWER

Syllabus which has been removed

Posted by Kapil Dalal 6 years ago

CBSE > Class 12 > Chemistry

4 answers

Vipul Kumar Maurya 6 years ago

Then why about 15th group is given in P Block revision notes??? This note should be according to syllabus.

0Thank You

Pragati Chaudhary 6 years ago

Mechanisms of polymer

2Thank You

Pragati Chaudhary 6 years ago

15th group elements of p-block

0Thank You

Sujal Samdarshi 6 years ago

Solid states

0Thank You

ANSWER

How inter halogen compound formed ? What general composition can be assigned to them ?

Posted by Pragati Chaudhary 6 years ago

CBSE > Class 12 > Chemistry

1 answers

Ankur Dahiya 6 years ago

First, 5:02 AM, what time is this friend. Were you studying the whole night or u wake up early? ?? Second, halogen is represented by R-X. Also known as haloalkanes maybe. Thats it. I just know this. Inform me when u get the answer.????

0Thank You

ANSWER

Give reason Oxygen has less electron gain with negative sign than sulphur

Posted by Pragati Chaudhary 6 years ago

CBSE > Class 12 > Chemistry

3 answers

Shubham Rajput 6 years ago

This is because of small size of oxygen as a result of which electrons of oxygen experiences repulsions among themselves and the incoming electron experiences it to;thus causing electron gain enthalpy to decrease (less negative)

1Thank You

Vishal Pathak 6 years ago

Also The electron gain enthalpy decreases down the group ..

0Thank You

Vidyanshu Sinha 6 years ago

Because of the compact nature of oxygen atom, it has less - ve electron gain enthalpy than sulphur.

1Thank You

ANSWER

On hydrolysis of RNA, no relationship among the quantities of different bases are obtained. Analyse the given information and suggest the structure of RNA.

Posted by Soyab Ali 6 years ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

How to end all chapters in 2 months

Posted by Suraj Gupta 6 years ago

CBSE > Class 12 > Chemistry

3 answers

Parul Singh 6 years ago

Complete atleast 2 chapter in one day

0Thank You

Geetanjali Rathod 6 years ago

We are having only 60 day ...and 45 appox chapter in main subject...so lear your self...one or two chapter daily and end of the day just review and do practice of chapter que...but give first priority to ncert

3Thank You

Rishabh Gupta 6 years ago

Study 10 hours per day Make a timetable for studies

0Thank You

ANSWER

Primary anime distngush

Posted by Rohan Sharma 6 years ago

CBSE > Class 12 > Chemistry

1 answers

Vanshita Gupta 6 years ago

You can use carbylamine reaction as it does give any reaction with secondary and tertiary amine or go for hinsberg reagent

0Thank You

ANSWER

Conversation of propanoic acid to ethanoic acid

Posted by Shun Shine Sharma 6 years ago

CBSE > Class 12 > Chemistry

1 answers

Aasta Chouhan 6 years ago

Propanoic acid react NH3 In heat to give propanamide which umder go offman bromide degradation to form ethanamine On reacting with nanO2 AND hcl give ethanol which on oxidation with kmno4 Give ethanoic acid

4Thank You

ANSWER

What do you mean by dancing resonance?

Posted by Ns H 6 years ago

CBSE > Class 12 > Chemistry

1 answers

Yogita Ingle 6 years ago

The resonance involving delocalization of sigma electrons (unlike the usual delocalization of pi electrons) is known as sigma resonance or dancing resonance. Eg. Resonance in cyclopropylmethyl carbocation.

1Thank You

ANSWER

Why are halogen coloured

Posted by Pragati Chaudhary 6 years ago

CBSE > Class 12 > Chemistry

4 answers

Ankur Dahiya 6 years ago

Pragati, colour is obtained by any metal or non metal by d orbital configuration. You can understand it in chapter 8 i.e. d- and f- block elements.

0Thank You

Vivekanand Yadav 6 years ago

Most halogens are coloured because tjey absorb light from visible region.

1Thank You

Pankaj Ku 6 years ago

d d transtion

0Thank You

Yogita Ingle 6 years ago

Most of the halogens are coloured because they absorb radiations which are in the visible region which in turn excite the valence electrons to higher energy levels. As the amount of energy which is required to excite the electrons to a higher level is different for different halogens, each halogen has a different colour.

0Thank You

ANSWER

What is chittar

Posted by Sameer Khan 6 years ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

Why aluminium cannot be reduced by carbon

Posted by Ashna Khan 6 years ago

CBSE > Class 12 > Chemistry

1 answers

Yogita Ingle 6 years ago

Carbon isn't utilized for diminishing aluminum oxide since aluminum is more responsive than carbon.

Thus, carbon can't uproot aluminum from its oxide.

Aluminum oxide is exceptionally steady and Carbon is less responsive than aluminum, hence it can't be utilized to diminish aluminum oxide to aluminum metal.

1Thank You

ANSWER

H2S is a toxic gas with rotten egg like smell is used for the qualitative analysis. If the solubility of H2s in water a stp is 0.195 m calculate henty'sLaw cinstant

Posted by Ankit Arya 6 years ago

CBSE > Class 12 > Chemistry

1 answers

Yogita Ingle 6 years ago

given, Molality =0.195 m,

Let take mass of solvent (water) = 1 kg

Use above formula we get

Moles of solute = 0.195 mol

Molar mass of water (H2O ) = 2 × 1 + 16 = 18

Mass of water (mass of solvent 1 kg = 1000 g

Number of moles of water = 1000 g / 18 = 55.56 mol

Use above formula we get

Mole fraction of H2S = 0.195/(0.195 + 55.56) = 0.0035

At STP, pressure (p) = 0.987 bar always

According to Henry’s law:

p = KH × X

KH = p / X = 0.987 / 0.0035 = 282 bar

0Thank You

ANSWER

2-bromo-2-methylpropane

Posted by Nitin Kumar 6 years ago

CBSE > Class 12 > Chemistry

2 answers

Geetanjali Rathod 6 years ago

Now u try the structure and send

0Thank You

Geetanjali Rathod 6 years ago

1st ..there is prop means 4 carbon atom then at second position methyl and bromo is attached (CH3 and Br ) =CH3C(CH3)(Br)CH2CH3...and check the carbon full with 4 valance atom...

1Thank You

ANSWER

Describe aldol condensation

Posted by M S 6 years ago

CBSE > Class 12 > Chemistry

2 answers

Yogita Ingle 6 years ago

Aldol condensation occurs in aldehydes having α-hydrogen with a dilute base to give β-hydroxy aldehydes called aldols. This reaction is most commonly known as aldol condensation. If the condensation reaction occurs between two different carbonyl compounds it is called crossed aldol condensation.

Aldol Condensation can be defined as an organic reaction in which enolate ion reacts with a carbonyl compound to form β-hydroxy ketone or β-hydroxy aldehyde, followed by dehydration to give a conjugated enone. Aldol Condensation plays a vital role in organic synthesis, creating a path to form carbon-carbon bonds.

1Thank You

Simardeep Singh 6 years ago

Aldol condensation means, condensation of alcohol and aldehyde to form alkene

1Thank You

ANSWER

What are chemical

Posted by Jitendra Chauhan 6 years ago

CBSE > Class 12 > Chemistry