Question

73克10%的鹽酸與80克氫氧化鈉溶液恰好完全反應(yīng)．求NaOH溶液中溶質(zhì)的質(zhì)量分數(shù)和所得溶液中溶質(zhì)的質(zhì)量分數(shù)．

Answer 1

【答案】分析：根據(jù)酸堿中和反應(yīng)的原理，酸與堿完全反應(yīng)所需的酸與堿的量相等來計算．
解答：解：設(shè)NaOH質(zhì)量為x，生成NaCl的質(zhì)量為y
NaOH+HCl=NaCl+H₂O
40      36.5   58.5
x      73g×10%  y
==
x=8g；y=11.7g
NaOH溶液中溶質(zhì)的質(zhì)量分數(shù)為NaOH%=×100%=10%
NaCl溶液中溶質(zhì)的質(zhì)量分數(shù)為NaCl%=×100%=7.6%
答：NaOH溶液中溶質(zhì)的質(zhì)量分數(shù)為10%；
NaCl溶液中溶質(zhì)的質(zhì)量分數(shù)為7.6%．
點評：要求學(xué)生熟練掌握酸堿中和反應(yīng)的原理，并根據(jù)酸堿中和反應(yīng)計算所需酸或堿的質(zhì)量以及生成物的質(zhì)量或質(zhì)量分數(shù)．