问题 选择题

以下是对某溶液进行离子检验的方法和结论,其中正确的是(  )

A.先加入BaCl2溶液,再加入HNO3溶液,产生了白色沉淀,则溶液中一定含有大量的SO42-

B.加入足量的CaCl2溶液,产生了白色沉淀,则溶液中一定含有大量的CO32-

C.加入盐酸,能产生使澄清石灰水变浑浊的气体,则溶液中一定含有CO32-

D.先加适量的硝酸将溶液酸化,再加入AgNO3溶液,产生了白色沉淀,则溶液中一定含有大量的Cl-

答案

A、能和氯化钡反应生成不溶于强酸的白色沉淀可能是氯化银,也可能是硫酸钡,硝酸具有强氧化性,能把亚硫酸钡氧化生成硫酸钡,所以原溶液中可能存在的离子是SO42-或SO32-或Cl-,也可能是SO42-、SO32-、Cl-中的两种或三种,故A错误;

B、能和氯化钙反应生成白色沉淀的阴离子有碳酸根离子、银离子,所以原溶液中可能存在的离子是碳酸根离子或银离子,故B错误;

C、能使澄清石灰水变浑浊的气体有二氧化碳和二氧化硫,所以原溶液中可能存在的离子可能是碳酸根离子、碳酸氢根离子、亚硫酸根离子、亚硫酸氢根离子,故C错误;

D、先将溶液用硝酸酸化后,排除了碳酸根离子的干扰,然后再加入硝酸银溶液,能产生白色沉淀的阴离子是氯离子,故D正确.

故选D.

阅读理解

I do not need a calendar to tell me when it is winter. All I need is my nose. When I wake up in the morning and smell the tasty treats my mom is cooking downstairs, I know winter has arrived.

The first one is the smell of chocolate. During the holiday season (from Thanksgiving to New Year’s Day) my mother makes her special hot chocolate. She always adds a peppermint candy cane (薄荷味拐棍糖) to the drink and tops it with cream.

The hot chocolate gets me out of bed, but it is my mother’s chocolate fudge (软糕) that makes me run downstairs. It is a thick chunk (块) of chocolate that tastes like heaven. My mother adds nuts. That gives it more texture (质感).

But my mother isn’t done yet. She also makes a treat she calls “window panes (窗玻璃)”. She takes a few different colored marshmallows (棉花糖) and melts them together with chocolate. The final product looks like a colorful church window, so we call it “window panes”.

These tasty holiday treats are usually eaten after a meal as a dessert. But don’t tell Santa Claus because I secretly eat them all day long.

小题1:What wakes “me” up in the morning?

A.The alarm clock.

B.My mom.

C.The noise upstairs.

D.The smell of food.小题2: In the author’s eyes, the taste of the chocolate fudge is ____.

A.terrible

B.wonderful

C.awful

D.so so小题3:With nuts, the chocolate fudge tastes _____.

A.softer

B.sweeter

C.harder

D.hotter小题4:The “window panes” the author mentions refer to _____.

A.special hot chocolate drink

B.decorations on the window

C.chocolate cake with fruits on it

D.a mixture of marshmallows and chocolate小题5:Why does the author look forward to the winter?

A.There is plenty of time to play around.

B.The food his mom cooks is mouthwatering.

C.It’s great fun to play outdoors.

D.He can have a good rest during the winter.

单项选择题