Question

1.

Which molecule or ion has the same molecular geometry as SeO₃^2–?

A.SO₃

B.NO₃^–

C.CO₃^2–

D.SO₃^2–

E.SeO₃

_2.

Which of the following processes is not exothermic?

A. Rb+(g)+e- = Rb(g)

B. Br(g)+e- = Br-(g)

C. Rb+(g)+Br-(g) = RbBr(s)

D. Rb(g) = Rb(s)

E. 1/2 Br2 (g) = Br(g)

Answer 1

1 ) answer : D.SO₃^2–

explanation:

(i) SeO₃^2– is pyramidal molecule hybridisation sp3. .SO₃^2–   here also S participate in sp3 hybridisation molecule shape is pyramidal

(ii) SO3 . in this moelcule S participate in sp2 hybridisation. molecule shape is planar

(iii) NO3- . N hybridisation sp2 . shape planar

(iv) CO3-2 . C hybridisation sp2 . shape planar

(v) SeO3 . se hybridisation sp2 . shape planar

2) answer: E). 1/2 Br2 (g) --------------> Br(g)

explanation :

A. Rb+(g)+e- --------------> Rb(g) --------------> electron affinity (exothermic)

B. Br(g)+e- ----> Br-(g) --------------> electron affinity (exothermic)

C. Rb+(g)+Br-(g) ----> RbBr(s)---------------> lattice energy (exothermic)

D. Rb(g) -----------> Rb(s) ----------------> compression of gas to solid (exothermic)

E. 1/2 Br2 (g) ---> Br(g)--------------> de-atomisation needs energy (endothermic)