Osmosis is the process in which solvent molecules moves through a semi-permeable membrane from a region of higher concentration to a region of lower concentration until the amount of fluid is equalised on both sides of the semipermeable membrane.  

Covalent compounds have bonds where electrons are shared between atoms. Due to the sharing of electrons, they exhibit characteristic physical properties that include lower melting points and electrical conductivity compared to ionic compounds. The melting point is low due to weak van der Waal's forces of attractions between the covalent molecules. The force of attraction between the molecules of a covalent compound is very weak.

Structure of Water Molecule

In water molecule, the oxygen is sp³ hybridized and hence has 4 sp³ hybridized orbitals. Two of these sp³ orbitals are half filled and hence overlap with 1s orbital of hydrogen to form two sp³ -s , O-H , σ bond while the other two contain a lone pair of electrons each.

The geometry of water molecule should be tetrahedral and the bond angle ∠HOH should be 109.5° but experimentally it has been determined that the actual bond angle is 104.5°.

Reason:

In water, the oxygen atom is surrounded by two shared pair ,and two lone pair of electrons. According to valence shell electron pair repulsion theory, lone pair- lone pair repulsion are stronger than Bond pair – Bond pair repulsion. As a result the bond angle in water is slightly smaller than the regular tetrahedral angle of 109.5°.The actual bond angle is 104.5° and each O-H  bond has a bond length of 95.7pm.

In the gaseous state, water exist as discrete molecules. It is a bent molecule with bond angle of 104.5° and bond length of 95.7 pm.

The electronegativity of oxygen is much higher than that of hydrogen and hence the shared pair of electrons in O-H bonds are attracted slightly more towards the oxygen atom. As a result oxygen carries a partial negative charge and hydrogen atoms carrier a partial positive charge. Since these two dipoles are inclined to each other at an angle of 104.5° therefore water is a highly polar molecule its actual dipole moment is 1.84 D.

Suppose volume of 10 M HCl required to prepare 1 L of 6 M HCl = x litre

 Volume of 3 M HCl required = (1-x) litre 

Applying molarity equation: 

Therefore Vol. of 10 M HCl required = 0.428 L = 428 mL. 

Vol. of 3 M HCl required = 1-0.428 = 0.527 L = 572 mL

On July 7, HRD Minister Ramesh Pokhriyal announced a major CBSE syllabus reduction with 30% of the syllabus slashed for the year 2020-21 for classes 9 to 12 because of the reduction in classroom teaching time due to the Covid-19 pandemic and lockdown.

CBSE has rationalized the syllabus with the help of suggestions from NCERT and the same has been notified by a new CBSE notification as well.

Click on the links:

Revised Syllabus: <a href="http://cbseacademic.nic.in/web_material/CurriculumMain21/revisedsyllabi/SrSecondary/REVISEDChemistry_2020-21.pdf">http://cbseacademic.nic.in/web_material/CurriculumMain21/revisedsyllabi/SrSecondary/REVISEDChemistry_2020-21.pdf</a>

Deleted portion:

<a href="http://cbseacademic.nic.in/web_material/CurriculumMain21/revisedsyllabi/Deduction/DELETEDChemistry_2020-21.pdf">http://cbseacademic.nic.in/web_material/CurriculumMain21/revisedsyllabi/Deduction/DELETEDChemistry_2020-21.pdf</a>

Answer :

• Molarity of the solution = 0.4 M.
• Normality of the solution = 0.8 N.

Step-by-step explanation :

Given that,

• Mass of  dissolved = 9.8 g.
• Volume of the solution = 250 cm³ = 0.250 L.

✒ Calculation of molarity :

Molar mass of 

∴ No. of moles of 

Now, 

✒ Calculation of normality :

Eq. mass of 

∴ No. of g equivalent of 

Now, 

The present set up of the Long Form of the Periodic Table can accommodate at the maximum 118 elements. After this, according to Aufbau principle, 8.y-orbital should be filled. Therefore, the outer electronic configuration of element having atomic number 119 will be 8s1. Since it has one electron in the outermost s-orbital, its valency will be 1 and it should belong to group 1 along with alkali metals. The general formula of its oxide will be M₂0, where M represents the element.

A homologous series is defined as a family or group of structurally similar organic compounds all the members of which contain the same functional group, Show a gradation in physical and similarity in chemical properties and any two adjacent members of which differ by a -CH₂ group. The individual members of such a series are called homologues and the phenomena is called homology.

Alkanes constitute a homologous series.

CH₄ Methane

C₂H₆ Ethane

C₃H₈ Propane

C₄H₁₀ Butane

A mole is defined as that amount of substance which contains Avogadro's number of atoms if the substance is atomic or Avogadro's number of molecules if the substance is molecular. 1 mole of carbon atoms = 6.022 ×10²³ atoms of carbon.

Limiting Reagent

• In a chemical reaction, reactant which is present in the lesser amount gets consumed after sometime and after that no further reaction takes place whatever be the amount of the other reactant present. Hence, the reactant which gets consumed, limits the amount of product formed and is, therefore, called the limiting reagent.

Problem:-

50.0 kg of N₂ (g) and 10.0 kg of H₂ (g) are mixed to produce NH₃ (g).

Calculate the NH₃ (g) formed. Identify the limiting reagent in the production of NH3 in this situation.