Give suitable statements
for the following
(1) Rain water conducts electricity but distilled water.
(ii) We feel burning sensation in the stomach when we overeat
(iii) A tarnished copper vessel regains its shine when
rubbed with lemon.
(iv) The crystals of washing soda change to white powder on exposure to air.
(v) An aqueous solution of sodium chloride is neutral but an aqueous solution of sodium carbonate is basic.
Answers
Give suitable statements
for the following
(1) Rain water conducts electricity but distilled water.
(ii) We feel burning sensation in the stomach when we overeat
(iii) A tarnished copper vessel regains its shine when
rubbed with lemon.
(iv) The crystals of washing soda change to white powder on exposure to air.
(v) An aqueous solution of sodium chloride is neutral but an aqueous solution of sodium carbonate is basic.
Explanation:
1)Distilled water is a pure type of water which does not contain any ions in it. ... These gases dissolve in water to form some kind of acids like carbonic acids which dissociates to give ions. Thus rainwater is conducting electricity while distilled water is not conducting electricity.
2)When we eat food, then Hydrochloric Acid is released in our stomach to help us digest that food properly. But, when we overeat, Hydrochloric Acid is produced in a greater amount, which makes our stomach acidic and leads to a burning sensation.
3)Lemon is acidic. ... Thus, on rubbing the tarnished copper vessel with lemon, the basic copper oxide or copper carbonate reacts with the acid (citric acid) present in the lemon to form a salt which is washed away with water.
4)When sodium carbonate crystals are exposed to air, they lose water of crystallization and turn to white powder. This process of loosing water of crystallization when exposed to air is called 'efflorescence'.
5)Aqueous solution of NaCl contains equal number of H+ and OH- ions,hence it is neutral in nature. On other hand,sodium carbonate is a salt of weak acid H₂CO₃ and strong base NaOH. ... Thus salt solution contains OH- ions. Hence aqueous solution of sodium carbonate is basic in nature.