The same thing is happening as with our bromothymol blue
情況和溴百里酚藍很類似
but this time when the solution is basic, it's pink
但這次，溶液呈堿性時，它是粉色
and when it's acidic, it's colorless
呈酸性時，則是無色
But why does adding dry ice
那么為什么加入干冰
change the solution from basic to acidic?
會讓溶液從堿性變?yōu)樗嵝阅?/p>
Well, dry ice is solid carbon dioxide
因為干冰是固態(tài)二氧化碳
When you add it to water, it bubbles
加到水中時，它會冒泡
and part of every bubble of carbon dioxide dissolves
每個泡泡中都會有二氧化碳溶解
when it does, it forms carbonic acid. Let's look at that equation
這時就會生成碳酸，我們來看看方程式
So there's more and more carbonic acid in the water
水中的碳酸越來越多
and this acid reacts with the sodium hydroxide until there's none left
這種酸會同氫氧化鈉反應(yīng)，一直將其耗盡為止
So the solution becomes acidic
于是溶液變成酸性
So we saw our bromothymol blue
所以我們看到溴百里酚藍
turning from blue to yellow as a solution became more acidic
隨著溶液酸性越來越強，從藍變黃
And we saw our phenolphthalein
而酚酞
turn from pink to colorless as it became more acidic
隨著溶液酸性越來越強，從粉色變?yōu)闊o色
Now let's watch again what happens in the final set of cylinders
下面再來看看最后一組柱形容器中的實驗
Alright, so now, I ask you to focus your attention on this cylinder
好，現(xiàn)在我要求你們注意這個柱形容器
Actually, you can focus your attention on anything you want to
實際上，你們也可以關(guān)注別的
You can even not pay attention if you want to
甚至不關(guān)注任何東西都行
We live in a free country
我們生活在一個自由的國度
But if you want to follow the experiment with me
但如果你想跟隨我的實驗步伐
I want you to focus your attention on this one
我希望你能關(guān)注這個
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