Chemical Reactions and Equations — Science STD 10 — Question

The elements whose oxides can turn phenolphthalein solution pink are:

On adding 2 mL acetic acid to 2 mL of water in a test tube, it was observed that:

Which of the following are exothermic processes?

1. Reaction of water with quick lime.
2. Dilution of an acid.
3. Evaporation of water.
4. Sublimation of camphor (crystals).

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

The two metals which can be extracted just by heating their sulphides in air are:

1. Sodium and copper.
2. Copper and aluminium.
3. Potassium and zinc.
4. Mercury and copper.

Reaction which has equal number of atoms of all the elements on both sides of a chemical equation is called

Which of the following are the correct characteristics of isotopes of an element?

1. Same atomic mass.
2. Same atomic number.
3. Same physical properties.
4. Same chemical properties.

1. (i), (ii) and (iv).
2. (ii), (iii) and (iv).
3. (ii) and (iii).
4. ​​​​​​​(ii) and (iv).

Carbon forms four covalent bonds by sharing its four valence electrons with four univalent atoms, e.g. hydrogen. After the formation of four bonds, carbon attains the electronic configuration of:

1. Helium.
2. Neon.
3. Argon.
4. Krypton.

Which of the following metals gives hydrogen with dil. HNO₃​?

Ethane, with the molecular formula C₂H₆ has:

Acetic acid was added to a solid X kept in a test tube. A colourless and odourless gas was evolved. The gas was passed through lime water which turned milky. It was concluded that.