Question

Consider the following statements and arrange in the order of true/false as given in the codes.
$S_1$: Ammonium chloride on heating with an aqueous solution of $K_{2}C{r}_2{C}_7$ and concentrated $H_{2}S{O}_4$ produces deep red vapours.

$S_2$: Deep red solution of ferric acetate on boiling with water turns to a brownish red solution.

$S_3$: $NaN{O}_2$ solution acidified with acetic acid produces blue colour with a starch paste contaminated with iodide ions.

• A. TTF
• B. FFT
• C. TFF
• D. FTT

Answer 1

The correct option is B FFT

$S_1$: Ammonium chloride on heating with an aqueous solution of $K_{2}C{r}_2{O}_7$ and concentrated $H_{2}S{O}_4$ produces chromyl chloride which then reacts with water to form chromic acid,thus preventing the formation of deep red vapours.
$Cr{O}_{2}C{l}_2+2H_{2}O\to H_{2}Cr{O}_4+2HCI$
$S_1$: Deep red solution of ferric acetate on boiling with water turns to a brownish red solution.
$(C{H}_{3}COO{)}_{3}Fe+H_{2}O\to Fe(OH{)}_2\left(C{H}_{3}COO\right)\downarrow \left(brownishredppt\right)+2C{H}_{3}COOH$
$S_3$: $NaN{O}_2$,solution acidified with acetic acid produces blue colour with a starch paste contaminated with iodide ions.
$N{O}_2^{-}+3I^{-}+4C{H}_{3}COOH\to I_3^{-}+2NO\downarrow +4C{H}_{3}CO{O}^{-}+2H_{2}O$
$I_2+starch\to bluesolution$