根據(jù)鋅與硫酸反應(yīng)生成硫酸鋅和氫氣，5g鋅全部反應(yīng)生成硫酸鋅及放出氫氣的質(zhì)量均為10g鋅全部反應(yīng)生成硫酸鋅質(zhì)量及放出氫氣質(zhì)量的一半；
根據(jù)質(zhì)量守恒定律，溶液的溶質(zhì)質(zhì)量分數(shù)為C₂的硫酸鋅溶液中溶液質(zhì)量小于溶液的溶質(zhì)質(zhì)量分數(shù)為C₁的硫酸鋅溶液中溶液質(zhì)量，而溶液的溶質(zhì)質(zhì)量分數(shù)為C₂的硫酸鋅溶液中溶質(zhì)質(zhì)量是溶液的溶質(zhì)質(zhì)量分數(shù)為C₁的硫酸鋅溶液中溶質(zhì)質(zhì)量的2倍；
根據(jù)溶液中溶質(zhì)質(zhì)量分數(shù)=

溶質(zhì)質(zhì)量

溶液質(zhì)量

×100%，可判斷得到C₁和C₂的大小關(guān)系為C₂＞2C₁；
故選C．