In which pair of ions both the species contain S-S bond?

$\left(\mathrm{a}\right) {\mathrm{S}}_2{\mathrm{O}}_7^{2-}, {\mathrm{S}}_2{\mathrm{O}}_3^{2-}$
$\left(\mathrm{b}\right) {\mathrm{S}}_4{\mathrm{O}}_6^{2-}, {\mathrm{S}}_2{\mathrm{O}}_3^{2-}$
$\left(\mathrm{c}\right) {\mathrm{S}}_2{\mathrm{O}}_7^{2-}, {\mathrm{S}}_2{\mathrm{O}}_8^{2-}$
$\left(\mathrm{d}\right) {\mathrm{S}}_4{\mathrm{O}}_6^{2-}, {\mathrm{S}}_2{\mathrm{O}}_7^{2-}$

AlF₃ is soluble in HF only in presence of KF. It is due to the formation of
(1) K₃[AIF₃H₃]

(2) K₃[AIF₆]

(3) AlH₃

(4) K[AIF₃H]

Hot concentrated sulphuric acid is a moderately strong oxidising agent. Which of the following reaction doe not show oxidising behaviour?

(a) Cu + 2H₂SO₄ $\to$CuSO₄ + SO₂ + 2H₂O

(b) 3S + 2H₂SO₄ $\to$3SO₂ + 2H₂O

(c) C + 2H₂SO₄ $\to$CO₂ + 2SO₂ + 2H₂O

(d) CaF₂ + H₂SO₄ $\to$CaSO₄ + 2HF

Among the following, which one is a wrong statement?

(1) PH₅ and BiCl₅ do not exist

(2) ρp-dp bonds are present in SO₂

(3) SeF₄ and CH₄ have same shape

(4) ${\mathrm{I}}_3^{+}$ has bent geometry

Copper on heating with concentrated HNO₃ produces:

1. Cu(NO₃)₂ and NO       

2. Cu(NO₃)₂, NO and NO₂

3. Cu(NO₃)₂ and N₂O       

4. Cu(NO₃)₂ and NO₂

Match the compounds given in column I with the hybridisation and shape given in column II and mark the correct option.

Column I     Column II
A. XeF₆        1. Distorted octahedral
B. XeO₃       2. Square planar
C. XeOF₄     3. Pyramidal
D. XeF₄       4. Square pyramidal

Codes
A B C D
(a) 1 2 4 3
(b) 4 3 1 2
(c) 4 1 2 3
(d) 1 3 4 2

The correct statement about given acids is:

The product obtained as a result of a reaction of nitrogen with CaC₂ is:

1. CaCN         

2. CaCN₃

3. Ca₂CN       

4. CaCN₂

Nitrogen dioxide and sulphur dioxide have some properties in common. Which property is

shown by one of these compounds. but not by the other?

1. Forms acid-rain

2. Is a reducing agent

3. Is soluble in water

4. ls used as a food-preservative

The maximum bond angle at nitrogen is present in which of the following?

1. NO₂

2. NO_2^-

3. NO_2⁺

4. NO3_^-