题目

 在t℃时，某NaOH稀溶液中，c(H＋)＝10－a mol/L，c(OH－)＝10－b mol/L，已知a＋b＝13，则在该温度下，将100 mL 0.10 mol/L的稀硫酸与100 mL 0.40 mol/L的NaOH溶液混合后，溶液的pH为（已知：忽略混合时体积的变化；lg2=0.30；lg3=0.48） A. 11.52    B. 11.70    C. 11.82    D. 12.00 答案：【答案】D 【解析】试题分析：t℃时，a＋b＝13，则KW=10-13。两溶液混合后，碱过量，溶液呈碱性，c（OH-）＝＝0.1mol/L,则c(H+)=KW/ c（OH-）=10-13/0.1mol/L＝10-12mol/L,pH=12。答案选D 考点：pH的计算完成句子。1. Tourists are becoming ______ (越来越感兴趣) in going climbing and boating. 2. ______ (在我看来), it was an honour to help you.3. It's ______ (有用) you ______ (带上)the map when you travel. 4. People travel to ______ (参观名胜古迹), and (了解) different cultures and customs. 5. Riding a camel ______ (穿越沙漠是有趣的经历).