25℃时，有浓度均为0.10mol/L的乙酸、乙酸钠两种溶液．请回答：_爱下问搜题

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问题问答题

25℃时，有浓度均为0.10mol/L的乙酸、乙酸钠两种溶液．请回答：两种溶液中，c（H⁺）＜c（OH^-）的是______（填“乙酸”或“乙酸钠”），其原因是______（用离子方程式表示）．两种溶液等体积混合后溶液显酸性，混合后溶液中各种离子的浓度由大到小依次为______．

答案

醋酸电离出氢离子导致溶液呈酸性，则c（H⁺）＞c（OH^-）；醋酸钠为强碱弱酸盐，醋酸根离子水解导致溶液呈碱性c（H⁺）＜c（OH^-），水解方程式为CH₃COO^-+H₂O⇌CH₃COOH+OH^-，两种溶液等浓度等体积混合后，混合溶液呈酸性，说明醋酸电离程度大于醋酸根离子水解程度，钠离子不水解，则c（CH₃COO^-）＞c（Na⁺）＞c（H⁺）＞c（OH^-），

故答案为：乙酸钠；CH₃COO^-+H₂O⇌CH₃COOH+OH^-；c（CH₃COO^-）＞c（Na⁺）＞c（H⁺）＞c（OH^-）．

完形填空

My friends and I had just finished lunch at a hotel when it started to rain heavily. When it became lighter, I decided to get my      , which was parked at my office three streets away.
My friends        that I shouldn’t go, mainly because I was seven months pregnant(怀孕) then. I promised them that I’d be very      . One of them wanted to come with me but I asked her to stay with another friend who needed help         her baby.
I walked out of the hotel and started making my way to the car. At the crossing, a van stopped and a man came out with an umbrella. Before I knew what was happening, he walked right      me and told me he’d escort(护送)me. Although I refused, he said that he would.
　　During our walk, he kept telling me to walk slower, as the ground was        . When we got to the car park, I thanked him and he went away. I did not get his name and can        recognize(认出) him now. Did he stop for me? I’ll never know.
　　So how did I pay it forward? I was at home when I noticed two Indian workers       in the heavy rain. They were probably on their way to the working place near my home. I went out and passed them my      . I told them they should take and keep it. They were surprised by my action. They were very grateful to me, probably          why a stranger was offering such kindness. I was so relaxed and happy that day.

多选题

某反应的△H=+100kJ•mol^-1，下列有关该反应的叙述正确的是（　　）

A．正反应活化能小于100kJ•mol^-1

B．逆反应活化能一定小于100kJ•mol^-1

C．正反应活化能不小于100kJ•mol^-1

D．正反应活化能比逆反应活化能大100kJ•mol^-1