Class 11th

This is a short answer type question as classified in NCERT Exemplar

In H₂O₂ oxygen is in -1 oxidation state which has tendency to become -2 that is why it is a better oxidising agent than water.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Option(i)

When the reaction is half completed, [A] = [B].
Thus, [B][A]=1
?G⁰=−RTInK=−RTIn(1)=0

This is a short answer type question as classified in NCERT Exemplar

2H₂O₂ → 2H₂O+O₂

5 volume H₂O₂ means IL of H₂O₂ will give 5L of O₂ at STP.

On the basis of the equation it is clear that 22.7 L of O₂ is produced by 68 g of H₂O₂.

5L of O₂ is produced by = $\frac{68g*51}{22.71}$  = $\frac{3400}{227}$ = g of H₂O₂=14.9g

i.e. 15 g H₂O₂ dissolved in 1 L solution will give 5 L oxygen or 1.5 g H₂O₂/100 mL solution will give 500 mL oxygen. Thus 15 g/L or 1.5% solution is known as the 5V solution of H₂O₂.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Option(iii)

The equation for weak acid and weak base is given as-

pH=7+ $\frac{1}{2}$  ?(pKa?−pKb?)

K_a=1.8*10^-5

pK_a=−log (1.8*10-5) =5−log1.8 =4.744

pK_b?=−log (1.8*10-5) =4.744

pH=7+ $\frac{1}{2}$  ?(pKa?−pK_b?) =7

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: option (i)

pH for weak acid is given by the following equation:

pH= $\frac{1}{2}$ [pK_a−logC]

= $\frac{1}{2}$ [−log (1.74*10⁻⁵)−log0.01]

=3.4

This is a short answer type question as classified in NCERT Exemplar

Peroxodisulphate, obtained by electrolytic oxidation of acidified sulphate solutions at high current density, on hydrolysis yields hydrogen peroxide.

2HSO₄^- (aq) → HO₃SOOSO₃ 2HSO₄^- (aq)+2H⁺ (aq)+H₂O₂ (aq)

This method is now used for the laboratory preparation Of D₂O₂.

K₂S₂O₈ (s)+2D₂O (l) → 2KDSO₄ (aq)+D₂O₂ (l)

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: option (iv)

Aqueous ammonia will absorb chloride ions and thus the equilibria will shift in forward direction and solubility of silver chloride will increase.

This is a short answer type question as classified in NCERT Exemplar

Heavy water can be made by electrolyzing water repeatedly or as a by-product in the fertiliser industry. It's a deuterium compound that's used to make other deuterium compounds.

Physical Properties of H₂O and D₂O

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: option (iii)

When 0.1 mol dm^-3 NH₄OH and 0.05 mol dm^-3 HCl react total amount of HCl reacts with NH₄OH to form NH₄Cl and some NH₄OH will be left unreacted. Thus, the resultant solution contains NH₄Cl and NH₄OH which will produce a buffer solution.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: option (iii)

 BF₃ is an electron deficient species that is why it is a Lewis acid. (all Lewis acid can accept a pair of electrons.