Question

Reaction A: $H_2\left(g\right)+F_2\left(g\right)\to 2\mathrm{HF}\left(g\right)$
Reaction B: $H_2\left(g\right)+I_2\left(g\right)\to 2\mathrm{HI}\left(g\right)$
Reaction C: $2H_2\left(g\right)+O_2\left(g\right)\to 2H_{2}O\left(l\right)$
Match the above reactions with the given options.

• A. occurs in darkness
• B. requires catalyst
• C. highly exothermic

Answer 1

Reaction A: Flourine $\left(F_2\right)$ reacts readily with hydrogen gas to give hydrogen flouride. This reaction occurs even in darkness.

Reaction B: Iodine $\left(I_2\right)$ reacts with hydrogen gas on heating in the presence of a catalyst to produce hydrogen iodide. This reaction requires a catalyst to progress.

Reaction C: Hydrogen gas reacts violently with oxygen gas to form water and liberates a very large amount of heat i.e, it is a highly exothermic reaction.