When metal $$'M'$$ is treated with $$NaOH$$ , a white gelatinous precipitate $$'X'$$ is obtained, which is soluble in excess of $$NaOH$$. Compound $$'X'$$ when heated strongly gives an oxide which is used in chromatography as an adsorbent. The metal $$'M'$$ is:
A.
$$Zn$$
B.
$$Ca$$
C.
$$Al$$
D.
$$Fe$$
Answer :
$$Al$$
Solution :
\[Al+3{{H}_{2}}O\xrightarrow{NaOH}\underset{\begin{smallmatrix}
\left( X \right) \\
\text{White gelatinous ppt}\text{. }
\end{smallmatrix}}{\mathop{Al{{\left( OH \right)}_{3}}\downarrow }}\,\] \[+\frac{3}{2}{{H}_{2}}\left( g \right)\]
\[Al{{\left( OH \right)}_{3}}\xrightarrow{\text{excess}\,\,\text{of}\,\,NaOH}\] \[\underset{\text{Soluble }}{\mathop{Na\left[ Al{{\left( OH \right)}_{4}} \right]}}\,\]
\[\underset{\left( X \right)}{\mathop{2Al{{\left( OH \right)}_{3}}}}\,\xrightarrow{\Delta }A{{l}_{2}}{{O}_{3}}+3{{H}_{2}}O\]
$$A{l_2}{O_3}$$ is used as adsorbent in chromatography. Thus,
metal $$'M'\,{\text{is}}\,Al.$$
Releted MCQ Question on Inorganic Chemistry >> P - Block Elements
Releted Question 1
The reddish brown coloured gas formed when nitric oxide is oxidised by air is