下列变化属于化学变化的是（   ）

名著阅读。

阅读理解Man or woman or a girl ?
One day, there is a man with long hair in the park. He is sitting on a chair, at this time an old man asks him, Is it a boy or a girl over there? She has long hair. I think she is a girl. Can you tell me?”
    “Yes. You are right. She is my daughter.”
    “Oh, I know. You must be the girl's mother.”
    “No， I'm her father.”The man is very angry（生气）.

化学与生产、生活密切相关，下列说法不正确的是（　　）

某无色溶液中只可能含有NH₄⁺、K⁺、Al³⁺、Fe³⁺、Cl^﹣、SO₄^2﹣等离子中的几种，现按下列步骤进行实验：

①该溶液的焰色反应呈现出紫色．

②取10mL该溶液于试管中滴加Ba（NO₃）₂溶液，加稀硝酸酸化后过滤得到0.03mol白色沉淀，向滤液中加入AgNO₃溶液未碱沉淀产生．

③另取10mL该溶液于试管中，滴加NaOH溶液产生白色沉淀，当沉淀增加到一定量后开始产生气体，最后沉淀完全溶解，并且随NaOH溶液的加入，沉淀和气体的变化关系如图所示：