What type of reaction is NH3 + H2SO4 (NH4)2 SO4

The reaction q+r2=r2q is found to be first order in r2 and

Indicate whether the specified alkyl halides will form primarily substitution products, only elimination products, both substitution and elimination products, or no products when they react with sodium methoxide. 1-bromobutane 1-bromo-2-methylpropane 2-bromobutane 2-bromo-2-methylpropane

Which statement describes james chadwick’s discovery.