The compound among the following with the lowest pK_a value is?

1. H₂O

2. H₂S

3. H₂Se

4. H₂Te

The shape of $Cl{O}_3^{-}$ is

(A) Tetrahedral

(B) Triangular planer

(C) Triangular pyramid

(D) Planer

Oxygen does not form OF₆ because

(A) It has a small size

(B) There are no vacant d- orbitals available

(C) It has high ionisation energy

(D) It has large size

The molecule having the smallest bond angle among the following is -

(1) H₂O

(2) H₂S

(3) H₂Te

(4) H₂Se

The oxide of a non-metal possesses the following characteristics:

The formula for 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

(A) SF₄ and S₂F₂

(B)  SF₆ and  SF₄ 

(C) NaF and NaCl

(D)  SF₄ and SF₆ 

Which of the following hydrides is the least poisonous?

1. ${\mathrm{NH}}_3$

2. ${\mathrm{PH}}_3$

3. ${\mathrm{AsH}}_3$

4. ${\mathrm{SbH}}_3$

On passing $H_{2}S$ through acidified $FeC{l}_3$ solution, $FeC{l}_3$ is converted into:

(1) $FeC{l}_2$

(2) $F{e}_2{(SO}_{}$₄)3

(3) FeS

(4) $FeS{O}_4$

The geometry of ${\mathrm{H}}_2\mathrm{S}$ and its dipole moment are:

(1) angular and non-zero

(2) angular and zero

(3) linear and zero

(4) linear and non-zero

$S{O}_2+H_{2}S\to product$. The final product is:

(1) $H_{2}O+S$

(2) $H_{2}S{O}_4$

(3) $H_{2}S{O}_3$

(4) $H_2{S}_2{O}_3$