Chemical Reactions and Equations — Science STD 10 — Question

The number of protons in one atom of an element X is 8. What will be the number of electrons in its ion X²⁻?

1. 8
2. 9
3. 10
4. 11

Vinegar is a solution of:

1. 50% – 60% acetic acid in alcohol.
2. 5% – 8% acetic acid in alcohol.
3. 5% – 8% acetic acid in water.
4. 50% – 60% acetic acid in water.

Lime water reacts with chlorine to give:

Plaster of Paris is made from:

Carbon's electronic configuration is:

To protect tooth decay we are advised to brush our teeth regularly. The nature of the tooth paste commonly used is:

1. Acidic.
2. Neutral.
3. Basic.
4. Corrosive.

The products of chlor-alkali process are:

1. NaCl, Cl₂ and H₂
2. H₂, Cl₂ and NaOH
3. Cl₂, Na₂CO₃ and H₂O
4. NaOH, Cl₂ and HCl

An element E reacts with water to form a solution which turns phenolphthalein solution pink. The element E is most likely to be:

1. S
2. Ca
3. C
4. Ag

In the neighbourhood of your school, hard water required for an experiment is not available. Select from the following groups of salts available in your school, a group each member of which, if dissolved in distilled water, will make it hard: