Question

An alkali metal A gives a compound B (molecular mass = 40 u) on reacting with

water. Then B gives a complex compound C on treatment with Zn. Identify A, B and

C and give the reactions involved.​

Answer 1

A is sodium because molar mass of NaOH is 40; which can be shown as follows:

Na(23)+O(16)+H(I)=40

So. B is NaOH

When sodium hydroxide is treated with aluminium oxide, we get sodium aluminate. So, C is sodium aluminate. Following reaction happens in this case:

Al

2

O

3

+2NaOH→2NaAlO

2

+H

2

O