Now, you might be thinking that all of the ion tests knowledge has been covered in other articles – and you’d be right. But really, who wouldn’t want a handy compilation article with everything in? Testing for both positive and negative ions, including halide, sulfate and nitrate ions, and looking at flame tests and other positive ion tests. More »
You may wonder why this article is here, given we’ve done an article on hard & soft water before – well, it’s because there’s some other stuff that you need to know about it, like how it is treated, detailed descriptions of removing hardness, and issues with hard and soft water – all in this article.
Sometimes in conjunction with flame tests, you can use sodium hydroxide to test for the presence of positive metal ions. This works because most ions with a +2 or +3 charge are insoluble in water. Therefore, when sodium hydroxide is added to a solution containing them, a hydroxide precipitate forms, containing the insoluble metal.
We can identify positive ions in different compounds or solutions by using a flame test. In a flame test, the flame will change colour depending on the ions present in the substance you’re testing.
Below is a table of different positive ions and their respective colour:
One potential issue with flame tests is that if there is more than one ion present, one colour could mask another. This is why you should also test with sodium hydroxide.
Everybody’s heard of hard and soft water – but do you know what the difference is? We know that they taste different, but why is that? Today, we’ll take a look at the differences in hard and soft water, and why they’re important.
Electrolysis is one of those topics that goes hand in hand with salts – and it’s a key thing to know, as it’s one of the topics that is fairly likely to come up on the C2 exam. But what is it? Here’s a quick guide to what electrolysis is, how it works, and a couple of processes it’s used for…