If the oxidation numbers of A, B, and C are + 2, +5, and –2 respectively, then the possible formula of the compound is:

1.	A2(BC2)2	2.	A3(BC4)2
3.	A2(BC3)2	4.	A3(B2C)2

A non-feasible reaction among the following is:

1. $2$ $\mathrm{KI}+{\mathrm{Br}}_2\to 2\mathrm{KBr}+{\mathrm{I}}_2$

2. $2$ $\mathrm{KBr}+{\mathrm{I}}_2\to 2\mathrm{KI}+{\mathrm{Br}}_2$

3. $2$ $\mathrm{KBr}+{\mathrm{Cl}}_2\to 2\mathrm{KCl}+{\mathrm{Br}}_2$

4. $2{\mathrm{H}}_2\mathrm{O}+2{\mathrm{F}}_2\to 4\mathrm{HF}+{\mathrm{O}}_2$

Standard electrode potentials are:

$F{e}^{+2}/Fe$ ,$E°$ $=$ $-0.\mathrm{44 }$

$\mathrm{ }F{e}^{+3}/F{e}^{+2} ,E°$ $=0.77$

Choose the correct observation if $F{e}^{+2},$ $F{e}^{+3}$, and Fe  block are kept together:

1. $F{e}^{+3}$ increases 

2. $F{e}^{+3}$ decreases 

3. $\frac{F{e}^{+2}}{F{e}^{+3}}$ remains unchanged 

4. $F{e}^{+2}$ decreases

The oxidation states(O.S.) of sulphur in the anions ${{\mathrm{SO}}_3}^{2-},$ ${\mathrm{S}}_2{{\mathrm{O}}_4}^{2-}$ $\mathrm{and}$ ${\mathrm{S}}_2{{\mathrm{O}}_6}^{2-}$ follow the order:

1. ${\mathrm{S}}_2{{\mathrm{O}}_4}^{2-}<{{\mathrm{SO}}_3}^{2-}<{\mathrm{S}}_2{{\mathrm{O}}_6}^{2-}$

2. ${{\mathrm{SO}}_3}^{2-}<{\mathrm{S}}_2{{\mathrm{O}}_4}^{2-}<{\mathrm{S}}_2{{\mathrm{O}}_6}^{2-}$

3. ${\mathrm{S}}_2{{\mathrm{O}}_4}^{2-}<{\mathrm{S}}_2{{\mathrm{O}}_6}^{2-}<{{\mathrm{SO}}_3}^{2-}$

4. ${\mathrm{S}}_2{{\mathrm{O}}_6}^{2-}<{\mathrm{S}}_2{{\mathrm{O}}_4}^{2-}<{{\mathrm{SO}}_3}^{2-}$

Fluorine reacts with ice as per the following reaction

H₂O(s) + F₂(g) → HF(g) + HOF(g)

This reaction is a redox reaction because-

The oxidation number of sulphur and nitrogen in H₂SO₅ and NO₃^- are respectively-

The formulas for the following compounds are: 

(a) Mercury(II) chloride  and (b) Thallium(I) sulphate

1. HgCl₂,  Tl₂SO₄

2. Hg₂Cl₂, Tl₂SO₄

3. HgCl₂,  TlSO₄

4. HgCl₂,  Tl₃SO₄

Consider the following reactions:

(a) 6 CO_2(g) + 6H₂O_(l) → C₆H₁₂O_6(aq) + 6O_2(g)

(b) O_3(g) + H₂O_2(l) → H₂O_(l) + 2O_2(g)

It is more appropriate to write these reactions as following

(a) 6CO_2(g) + 12H₂O_(l) → C₆H₁₂O_6(aq) + 6H₂O_(l) + 6O_2(g)

(b) O_3(g) + H₂O_2(l) → H₂O_(l) + O_2(g) + O_2(g) 

because:

1. Water molecules are also the product of photosynthesis

2. Water molecules are not a product of photosynthesis.

3. Oxygen molecules are also the product of photosynthesis.

4. Oxygen molecules are not a product of photosynthesis.

In the manufacture of benzoic acid from toluene, we use alcoholic potassium permanganate as an oxidant because -

1. The cost of adding an acid or a base can be reduced.

2. The reactions can proceed at a faster rate.

3. Both '1' and '2'

4. Neither '1' nor '2'

Consider the following reactions :

2 S₂O₃^2–_(aq) + I_2(s) → S₄O₆^2–_(aq) + 2I^–_(aq)

S₂O₃^2–_(aq) + 2Br_2(l) + 5H₂O_(l) → 2SO₄^2–_(aq) + 4Br^–_(aq) + 10H⁺_(aq)

The same reductant, thiosulphate react differently with iodine and bromine because-

1. Br₂ is a stronger oxidizing agent than I₂

2. I₂ is a stronger oxidizing agent than Br₂

3. Both '1' and '2'

4. Neither '1' nor '2'