Question

Identify the correct statement(s):

• A. The oxidation number of Cr in $CrO_{5}$ is + 6.
• B. $\Delta H >\Delta U$ for the reaction $N_{2}O_{4}\left(g\right)\rightarrow2NO_{2} \left(g\right),$provided both gases behave ideally.
• C. pH of 0.1N $H_{2}SO_{4}$ is less than that of 0.1N HCl at 25?C.
• D. $\binom{RT}{F}$ =0.0591 volt at 25?C.

Answer 1

Answer: (B)

$\Delta H >\Delta U$ for the reaction $N_{2}O_{4}\left(g\right)\rightarrow2NO_{2} \left(g\right),$provided both gases behave ideally.

Answer 2

(B)$N_{2}O_{4} \left(g\right) \to2NO_{2} \left(g\right), \Delta H =\Delta U +\Delta n_{g}RT =\Delta U +\left(2-1\right)RT =\Delta U+RT$
$\therefore\bigtriangleup H >\Delta U\because$ Reaction is endothermic
(C) For 0.1N $H_{2}SO_{4}$ solution, $\left[H^{+}\right]=0.1N\therefore pH=1$
For 0.1NHCl solution,$\left[H^{+}\right]=0.1N\therefore pH=1$ same
(D) is incorrect as $\frac{RF}{F} =$ $\frac{8.314\times298}{96500} =0.0256V$