Why should the government consider the price elasticity of demand when imposing tax on goods?

The price elasticity of demand tells you how sensitive consumers are to a change in the price of a good. Therefore the more sensitive (elastic) the demand is, the more the tax will effect the demand. So, if the good has a relatively inelastic demand then a tax would cause relatively less percentage change in demand compared to the percentage change in price. This is the case for goods such as cigarettes, as they are addictive the demand is inelastic hence a tax would only marginally reduce demand. Thus if the aim of the government was to reduce the amount consuming cigarettes the PED would allow the government to realise that they should undertake different methods to deter consumers from purchasing cigarettes. Hence the PED helps the government foresee the result of the tax they would be imposing.