Carbon and its Compounds — Science STD 10 — Question

If a few drops of a concentrated acid accidentally spills over the hand of a student, what should be done?

1. Wash the hand with saline solution.
2. Wash the hand immediately with plenty of water and apply a paste of sodium hydrogencarbonate.
3. After washing with plenty of water apply solution of sodium hydroxide on the hand.
4. Neutralise the acid with a strong alkali.

If the pH value of a solution is greater than 7, solution is:

Which of the following elements will form an acidic oxide?

1. An element with atomic number 7.
2. An element with atomic number 3.
3. An element with atomic number 12.
4. An element with atomic number 19.

The elements whose oxides can turn litmus solution blue are:

The colour of raisins as used in the experiment, 'to determine the percentage of water absorbed by raisins' was.

Sodium hydrogencarbonate when added to acetic acid evolves a gas. Which of the following statements are true about the gas evolved?

1. It turns lime water milky.
2. It extinguishes a burning splinter.
3. It dissolves in a solution of sodium hydroxide.
4. It has a pungent odour.

1. 1 and 2
2. 1, 2 and 3
3. 2, 3 and 4
4. 1 and 4

What is the chemical name of a substance used in white washing?

The elements A, B, C, D and E have atomic numbers 9, 11, 17, 12 and 13 respectively. The pair of elements which belongs to the same group of the periodic table is:

1. A and B.
2. B and D.
3. A and C.
4. D and E.

Which of the following pair of metals exists in their native state in nature?