3.71 When potassium cyanide (KCN) reacts with acids, a deadly poisonous gas,
hydrogen cyanide (HCN), is given off. Here is the equation:
KCN(aq) + HCl(aq) -> KCl(aq) + HCN(g)
If a sample of 0.140 grams of KCN is treated with an excess of HCl,
calculate the amount of HCN formed, in grams.