Which reaction can not be used for the preparation of halogen acid

$\left(A\right) 2KBr +H_{2}S{O}_4(conc.) \to K_{2}S{O}_4 +2HBr$
$\left(B\right) NaCl +H_{2}S{O}_4(conc.) \to NaHS{O}_4 +HCl$
$\left(C\right) NaHS{O}_4 +NaCl \to N{a}_{2}S{O}_4 +HCl$
$\left(D\right) Ca{F}_2 +H_{2}S{O}_4(conc.) \to CaS{O}_4 +2HF$

An element (X) forms compounds of the formula $XC{l}_3, X_2{O}_5 and C{a}_3{X}_2,$but does not form X$C{l}_5$. Which of the following is the element

(1) B

(2) Al

(3) N

(4) P

Oxygen does not form OF₆ because

1. It has a small size

2. There are no vacant d- orbitals available

3.  It has high ionization energy

4. It has a large size

The molecule having the smallest bond angle is

(1) H₂O

(2) H₂S

(3) H₂Te

(4) H₂Se

The correct statement regarding H₃PO₃ is:

1. Each hydrogen atom is attached to oxygen.

2. Two hydrogen atoms are attached to oxygen atoms.

3. One atom of H is attached to oxygen.

4. None of the above.

Strong oxidising agent and strong reducing agents are respectively

(1) F₂, HI

(2) Cl₂, HCl

(3) Br₂,HBr

(4) I₂, HF

Oxide of a non-metal possesses the following characterstics.

(i) It is both a proton donor and proton acceptor

(ii) It is poor conductor of electricity

(iii) It reacts readily with basic and acidic oxides

(iv) It oxidises Fe at boiling point.

The oxide is

(1) H₂O

(2) CO₂

(3) H₂O₂

(4) NO

A yellow metallic powder is burnt in a stream of fluorine to obtain a colourless gas X which is thermally stable and chemically inert. Its molecule has octahedral geometry. Another colourless gas Y with same constituent atoms as that of X is obtained when sulphur dichloride is heated with sodium fluoride. Its molecule has triangular pyramidal structure X and Y are

(1) SF₄ and S₂F₂

(2)  SF₆ and  SF₄ 

(3) NaF and NaCl

(4)  SF₄ and SF₆ 

The shape and the type of hybridization (of the Cl-atom) in  the CIF₃ molecule

1.		2.
3.		4.

In the nitrogen family, the H-M-H bond angle in the hybrides MH₃ gradually becomes closer to 90^o if we move from N to Sb. This shows that gradually