Everyday Chemistry — Common Names, Formulas and Uses You Must Recall Instantly

This is the cheapest chapter in general science. There is nothing to derive, nothing to balance and nothing to calculate — you either recall that washing soda is Na₂CO₃·10H₂O or you do not. Yet it appears every single year: two to three questions in SSC CGL and CHSL, one or two in Railway NTPC and Group D, and it sits inside the general science portion of BPSC TRE-4 and CTET as well.

What makes students lose these easy marks is not ignorance, it is confusion between near-twins. Baking soda and washing soda are both sodium carbonates. Plaster of Paris and gypsum are both calcium sulphates. Quick lime and slaked lime differ by one water molecule. Blue and green vitriol differ only by the metal. The paper knows this, and it sets the twin as the distractor almost every time. So learn these in pairs, never alone.

1. What is the chemical formula of washing soda?

2. Plaster of Paris, used to set fractured bones, has the formula:

3. Bleaching powder, used to disinfect drinking water, is chemically:

4. Blue vitriol (nila thotha) is:

5. The acid present in the sting of an ant is:

6. "Marsh gas" consists mainly of:

7. Aqua regia, which can dissolve gold, is a mixture of concentrated HCl and concentrated HNO₃ in the ratio:

8. Which pair of common name and chemical name is correctly matched?