Question

Potassium cyanide (KCN) reacts with acids to form a deadly poisonous gas, hydrogen cyanide (HCN). The reaction is represented by the equation:

KCN(aq) + HCl(aq) è KCl(aq) + HCN(g)

If a sample of 0.150 g of KCN is treated with an excess of HCL, calculate the amount of HCN produced, in grams.

Answer 1

KCN(aq) + HCl(aq) ------> KCl(aq) + HCN(g)

calculate the moles of KCN using weigt / molar mass formula

moles of KCN = 0.15 / 65.12

= 0.0023 moles

from reaction it is clear that one mole of KCN will produce one mole of HCN

0.0023 moles of KCN produce 0.0023 moles of HCN

weight of HCN = moles of HCN x molar mass of HCN

= 0.0023 x 27.03

= 0.0623 grams.