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

Options

A. Zn
B. Ca
C. Al
D. Fe

Answer

C

Explanation

`Al+3H_(2)O overset(NaOH) rarr underset("White gelatinous ppt")(underset("(x)")(Al(OH)_(3))darr +3//2H_(2) (g))`
`Al(OH)_(3) overset("excess of NaOH")rarr underset("Soluble") (Na[Al(OH)_(4)])`
`underset("(X)")(2Al(OH)_(3)) overset(Delta)rarr Al_(2)O_(3) +3H_(2)O`
`Al_(2)O_(3)` is used as adsorbent in chromatography. Thus, metal .M. is Al.