Choose the correct statements about the hydrides of group 15 elements.

A. The stability of the hydrides decreases in the order $$\mathrm{NH}_3>\mathrm{PH}_3>\mathrm{AsH}_3> \mathrm{SbH}_3>\mathrm{BiH}_3$$.

B. The reducing ability of the hydride increases in the order $$\mathrm{NH}_3<\mathrm{PH}_3<\mathrm{AsH}_3 <\mathrm{SbH}_3<\mathrm{BiH}_3$$.

C. Among the hydrides, $$\mathrm{NH}_3$$ is strong reducing agent while $$\mathrm{BiH}_3$$ is mild reducing agent.

D. The basicity of the hydrides increases in the order $$\mathrm{NH}_3<\mathrm{PH}_3<\mathrm{AsH}_3< \mathrm{SbH}_3<\mathrm{BiH}_3$$.

Choose the most appropriate from the options given below :

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R:

Assertion A: $$\mathrm{H}_2 \mathrm{Te}$$ is more acidic than $$\mathrm{H}_2 \mathrm{~S}$$.

Reason R: Bond dissociation enthalpy of $$\mathrm{H}_2 \mathrm{Te}$$ is lower than $$\mathrm{H}_2 \mathrm{~S}$$.

In the light of the above statements, choose the most appropriate from the options given below:

Alkaline oxidative fusion of $$\mathrm{MnO}_2$$ gives "A" which on electrolytic oxidation in alkaline solution produces B. A and B respectively are

Salicylaldehyde is synthesized from phenol, when reacted with