Question

$\underset{\text{Black}}{X(S)}\stackrel{\text{ dil }HCl}{\to }Y\uparrow \underset{NaOH}{\overset{N{a}_2[Fe(CN{)}_5(NO)]}{\to }}$
Purple solution gas $Y$ has been allowed to react with following species in neutral/acidic medium:
(a) $FeC{l}_3$
(b) $CuS{O}_4$
(c) $BaC{l}_2$
(d) $S{O}_2$
(e) $C{r}_2{O}_7^{2-}$
(f) $C{H}_{3}COONa$
(g) $H{g}_2^{2+}$
Then calculate value of $(P+Q-R)$
$P$ : Number of species which undergoes redox reaction with gas $Y$.
$Q$ : Number of species with which gas $Y$ undergoes precipitation.
$R$ : Number of species with which gas $Y$ produce no observable change.

Answer 1

Answer: 4.00