For 1 mole of C2H5NH2 (ethyl amine), 2 moles of CH3Cl (methyl chloride) are required to form 3∘ amine. As given 90g of ethyl amine, hence 2 moles of C2H5NH2. Because molecular weight of C2H5NH2 is 45g. So, for 1 mole C2H5Cl
2CH3Cl
⟶
3∘ amine For 2 moles C2H5Cl
4CH3Cl
⟶
3∘ amine Molecular weight of CH3Cl=50.49g∕mol Hence, amount of methyl chloride required =4×50.49=201.96∼eq202g