Question

向l00g10%NaOH溶液中加入12.5gNaOH固體，完全溶解后．所得溶液中溶質(zhì)質(zhì)量分?jǐn)?shù)為（ ）
A．12.5%
B．20%
C．22.5%
D．25%

Answer 1

【答案】分析：加入12.5gNaOH固體完全溶解后，所得溶液中溶質(zhì)質(zhì)量為原溶液中溶質(zhì)質(zhì)量與后加入的氫氧化鈉質(zhì)量之和，溶液質(zhì)量為原溶液質(zhì)量與所加入氫氧化鈉質(zhì)量之和．
解答：解：所得溶液中溶質(zhì)質(zhì)量分?jǐn)?shù)=×100%=20%
故選B．
點(diǎn)評(píng)：根據(jù)溶質(zhì)的質(zhì)量分?jǐn)?shù)=×100%，分析出溶液中溶質(zhì)質(zhì)量、溶液質(zhì)量即可利用公式計(jì)算溶液的溶質(zhì)質(zhì)量分?jǐn)?shù)．