Ncert Solutions Chemistry Class 11th

This is a Short Answer Type Questions as classified in NCERT Exemplar

Ans: BF₃ does not have a proton but still it acts as a Lewis acid as it is an electron pair acceptor and reacts with NH₃by accepting its lone pair of electrons. The reaction can be represented by Coordinate bond is formed between BF₃ and NH₃. It can be represented as-

  [ BF₃ ← :NH₃]

Nitrogen acts as lone pair donator in this combination

This is a Short Answer Type Questions as classified in NCERT Exemplar

Ans: Conductance of a solution depends upon the number of ions present in the solution since sodium chloride is an ionic compound when mixed in water it ionizes completely forming an aqueous electrolytic solution. Hence, the solution conducts electricity while sugar being a non-electrolyte does not ionize in water and when concentration of NaCl is increased, more Na⁺ and Cl^-  ions will be produced. Hence, conductance increases.

This is a Short Answer Type Questions as classified in NCERT Exemplar

Ans: Conjugate acid and conjugate base can be shown as-

HCl(aq) + H₂O (l) ? H₃O⁺(aq) + Cl^-(aq) 

 acid        base        conjugate    conjugate

                             acid          base

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

It is lithium hydride (LiH) because it has significant covalent character due to the smallest alkali metal, LiH is very stable. It is almost nonreactive towards oxygen and chlorine. It reacts with Al2Cl2 to form lithium aluminium hydride.

8LiH+ Al₂Cl₆ → 2LiAlH₄ → LiCl

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

Since, a colourless liquid 'A' contains only hydrogen and oxygen and decomposes slowly on exposure to light but is stabilised by addition of urea, therefore, liquid A may be hydrogen peroxide. A is H₂O₂. 

Structure of H₂O₂ is given below.

This is a Long Answer Type Questions as classified in NCERT Exemplar

Ans: The equation can be written as-

A^p+_x  +  B^q- _y ? xA^p+ (aq) +  yB^q-

S moles of A and B dissolves to give x S moles of A^p+ and y S moles of Bq-.

K_sp = [A^p+]^x  [B^q-]^y = [x5]^x [y5]^y

= x^x y ^y 5 ^x+y

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

Mass of H₂O₂ = 68 g.

Mol. Mass of H₂O₂=34gmol^-1

∴1L of M solution of H₂O₂ will contain H₂O₂=34*5 g

∴2L of 5 M solution will contain H₂O₂=34*5*2=340g

or 200 mL of 5 solution will contain H₂O₂ = $\frac{340}{2000}$ $*$  200 = 34 g

Now 2H₂O₂ → 2H₂O+O₂

           64 g  32g

Now 68 g of H₂O₂ on decomposition will give O₂=32g

∴34g of H₂O₂ on decomposition will give O₂ = $\frac{34}{68}$ $*$    34 =16 g

(i) Industrial preparation: H₂O₂ is prepared by the auto-oxidation of 2- alkylanthraquinols

2-ethylanthraquinol ↔ H₂O₂⁺ oxidised product

2Fe₂+ (aq)+2H+ (aq)+H₂O₂ → Fe3 (aq)+2H₂O (l)

PbS (s)+4H₂O₂ (l) → PbSO4 (s)+4H₂O (l)

(ii) Reducing action of hydrogen peroxide 

2MnO₄^-+6H⁺+5H₂O₂→ 2Mn²⁺+8H₂O+5H₂

HOCl+H₂O₂ → H₃O⁺+Cl^-+O₂

Oxidising action of hydrogen peroxide 

2Fe²⁺+H₂O₂→ 2Fe³⁺+2OH^-

Mn²⁺+H₂O₂ → Mn⁴⁺+2OH^-

Acidic properties of H₂O₂

I₂+H₂O₂+2OH^-→ 2I^-+2H₂O+H₂

2MnO₄^-+3H₂O₂→ 2MnO₂+3O₂+2H₂O+2OH^-