Question

A soft silver-white metal (A) burns with golden yellow flame to give a yellow power B which on treatment with water liberates oxygen giving a clear solution C. The solution placed on Al attacks this metal, liberating a gas D and forming a water soluble compound E. The metal (A) dissolves in liquid $N{H}_3$ to form deep blue solution which is a good conductor and an excellent reducing agent. Identify E.

• A. $NaOH$
• B. $NaAl{O}_2$
• C. $Ca(Al{O}_2{)}_2$
• D. None ofthese

Answer 1

The correct option is B $NaAl{O}_2$

The lithium flame is bright red, sodium shows yellow flame where as, potassium shows violet flame. According to passage a soft silver white metal (A) burns with golden yellow flame to give a yellow power B which on treatment with water liberates oxygen giving a clear solution.
$2N{a}_2+O_2\to 2N{a}_{2}O$
$N{a}_{2}O$ on treatment with water liberates oxygen giving a clear solution.
$2N{a}_2{O}_2+2H_{2}O\to 4NaOH+O_2$
The solution placed on AI attacks this metal, liberating a gas and forming a water soluble compound .
$2Al+2NaOH+2H_{2}O\to 2NaAl{O}_2+3H_2$
Hence, the final option is $NaAl{O}_2$.