Which of the following oxide(s) is/are soluble in water to form alkalis?

(i) Na₂O

(ii) SO₂

(iii) K₂O

(iv) NO₂

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

Study the diagram given below and identify the gas formed in the reaction.

1. Carbon di-oxide which extinguishes the burning candle.
2. Oxygen due to which the candle burns more brightly.
3. Sulphur dioxide which produces a suffocating smell.
4. Hydrogen which while burning produces a popping sound.

Which of the options in the given table are correct?

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

C₆H₁₂O₆ (aq) + 6O₂ (aq) ⟶ 6CO₂ (aq) + 6H₂O (l)

The above reaction is a/an

1. displacement reaction
2. endothermic reaction
3. exothermic reaction
4. neutralisation reaction