某兴趣小组同学为证明NaOH溶液与稀盐酸发生了中和反应，从不同角度设计了如下实验方案，并进行实验。

方案一：先用pH试纸测定NaOH溶液的pH，再滴加盐酸，并不断振荡溶液，同时测定混合溶液的pH，如果测得的pH逐渐变小且小于7，则证明NaOH溶液与稀盐酸发生了化学反应。

(1)用pH试纸测定溶液的pH时，正确的操作是：__________________________________。

(2)简述强调“测得的pH小于7”的理由：______________________。

方案二：先在NaOH溶液中滴加几滴酚酞溶液，溶液显红色，然后再滴加盐酸，可观察到红色逐渐消失，则证明NaOH溶液与稀盐酸发生了化学反应。该组同学在向NaOH溶液中滴加酚酞溶液时，发现了一个意外现象：氢氧化钠溶液中滴入酚酞溶液，溶液变成了红色，过了一会儿红色就消失了。该小组对这种意外现象的原因作了如下猜想：①可能是酚酞溶液与空气中的氧气反应，使红色消失；②可能是氢氧化钠溶液与空气中的二氧化碳反应，使红色消失。

(3)为验证猜想①，该组同学做了如下实验：将配制的氢氧化钠溶液加热，并在液面上方滴一些植物油，然后在冷却后的溶液中滴入酚酞溶液。实验中“加热”和“滴入植物油”目的是______________。实验结果表明酚酞溶液红色消失与空气中的氧气无关。

(4)为验证猜想②，该组同学做了如下实验：取了一定量的Na₂CO₃溶液，在其中滴入酚酞溶液，发现溶液也呈现红色，由此可得出以下两点结论：

结论1：说明Na₂CO₃溶液呈_______性；

结论2：说明酚酞溶液红色消失与空气中的二氧化碳无关。

(5)该小组同学通过查阅资料得知：当氢氧化钠溶液浓度很大时，就会出现上述意外现象。请设计实验证明该方案中取用的NaOH溶液浓度过大：

①实验方法_________________________________________________，②观察到的现象_________________________________________________________。

方案三：化学反应中通常伴随有能量的变化，可借助反应前后的温度变化来判断反应的发生。如果NaOH溶液与稀盐酸混合前后温度有变化，则证明发生了化学反应。该组同学将不同浓度的盐酸和NaOH溶液各10mL混合，用温度计测定室温下混合前后温度的变化，并记录了每次混合前后温度的升高值△t（如下表）。

(6)表中x=___________。

(7)某同学在没使用温度计的情况下，通过下图所示装置完成了实验。则该同学根据______________判断NaOH溶液与稀盐酸发生了中和反应。

(8)关于实验中的细节和意外情况：

①实验中，稀盐酸必须用胶头滴管逐滴滴加，这样做的目的是___________________。

②实验过程中，要用玻璃棒不断搅拌，这样做的目的是___________________。

③在实验过程中意外发现有气泡出现，你认为原因是_____________________。

④发现盛放NaOH溶液的试剂瓶瓶口和橡皮塞上出现了白色粉末。他们依据所学的化学知识，对这种白色粉末的成分作了如下猜想：①可能是NaOH；你认为：②可能是__________；③可能是__________。

根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。

选项中有两项为多余选项。

    Women's roles have changed throughout the world in recent years, but nowhere so obviously as

in America .1________ .In many American homes today ,the husband still carries on his traditional

role of breadwinner ,while his homemaker wife is in charge of the home and child-raising. But it is more

and more common to find that the children are left in day -care centers or nursery schools while both

parents work 2___________. At home, household duties are shared in varying degrees by all family

members .It is not unusual to find father cooking dinner, cleaning the living room or changing the baby

.3 ______.Children have responsibilities, too .One of the goals of the Women's Liberation Movement

has been to have both men and women share in childcare, housework and financial responsibility.

4 _ ____.

   The high cost of living has made it necessary for many women to have jobs outside the home ,but

women often choose to have jobs in order to use their skills and education or to seek a more fulfilling

and interesting life .Many American women enjoy the independence that an outside job and the salary

give men and even some women-sometimes are not for women working outside the home ,and in some

cases ,a woman might be paid less than a man who performs the same job .5__  __.

A. As the roles of women have changed, so have men's

B. The woman may earn as much or more money than her husband

C. Mother might be outside mowing the lawn or washing the car

D. Today many American women will not marry a man who is not willing to share equally in household responsibilities

E. American women, however, have met challenges(挑战)since pioneer days ,and they continue to work for true equality

F. women didn't play an important role in the past

G. women in America were not happy in the past