Answer: For safety
Explanation: One of the biggest reason why the water we use are treated is so that it is safe for us to use.
P is the chemical symbol for phosphorus.
Cl is the chemical symbol for chloride, and there are three of them - the prefix for three is tri-.
The molecules of two different elements, nitrogen and oxygen, make up about 99 percent of the air.
have a good day !! :)
1 - a, 2-b, 3-d, 4 - e
<u>Explanation:</u>
<u></u>
- Separated by 6M HCl
Silver and aluminum ions can be separated using the acid, 6M HCl.
- Separated by H₂S
Copper and Calcium ions can be separated by the reagent hydrogen sulfide, H₂S.
- Separated by (NH₄)₂HPO₄ in NH₃
Magnesium and Potassium ions can be separated by the reagent Ammonium hydrogen phosphate in ammonia.
- cannot be separated
Nickel and Cobalt ion cannot be separated by the reagents given at all.