根据短文内容, 完成下列各题。

    Jack's friend Sally isn't fine these days.

    One day she asks Jack for help. And she tells (告诉) Jack about her eating habits. For breakfast, she always eats some bread. For lunch, she always has some chicken. She likes eating ice-cream and a hamburger in the evening.

 “They're not healthy for you, Sally,” Jack says.

 “I know, but I like them,” Sally says.

 “What about vegetables? Do you like eating carrots?” Jack asks.

 “No, I don't,” Sally says.

 “Sally, don't eat ice-cream. You must eat some vegetables and fruit. They are good for you.” Jack says.

 “I think you're right,” Sally says.

    In the next days, Sally always eats vegetables and fruit. And she is well now.

氢氧化钠是化学实验室中常用的试剂。 
（1）氢氧化钠固体曝露在空气中，容易吸收水分而使表面覆盖一层溶液（这一现象又叫“潮解”）；它还能____，这一变化的化学方程式可表示为：____。所以氢氧化钠固体必须____保存。
(2)向盛有氢氧化钠溶液的锥形瓶里滴入几滴酚酞溶液，溶液变成红色，pH >7，逐滴向锥形瓶中滴入盐酸并振荡，观察到的现象是____，溶液的pH____（填“增大”或“减小”）， 反应的化学方程式为____ ；
(3)有一瓶溶液pH是4.5，如果要使溶液的pH升高，可以用____的方法。

____是一种添加剂，食品中添加食用色素，可以改变食品的外观和口味。