Can anyone help me by answering these questions? It's MCQ....
1) When sodium bicarbonate powder is added to acetic acid, a gas evolves. Which one of the following statements is NOT true about the gas?
(A) Turns lime water milky
(B) Colourless and odourless
(C) Extinguishes with a burning splinter
(D) Burns with a pop sound
2) Water stored underground is always better. Pick one point which works against this statement.
(A) It does not evaporate
(B) It acts as breeding ground for mosquitos
(C) It does not get polluted by human and animal wastes
(D) It will recharge wells
Answers
Answer:
1-D
2-B
Explanation:
1-As CO2 which is evolved does not burns with a pop sound
2-How can you tell something negative about rainwater harvesting:)
1) The evolved gas doesn't burn with a pop sound. (Option D)
• In the chemical reaction between the sodium bicarbonate and acetic acid,the carbon dioxide gas is evolved.
Now,we all know that carbon dioxide is not combustible at all and that's why the statement mentioned in the option D is incorrect about the carbon dioxide gas.
2) It acts as breeding ground for the mosquitoes is the statement which is against for the ground water. (Option B)
• Although this mosquito breeding in the groundwater is not true because the groundwater is situated far from the ground level and it is unreachable for the mosquitoes.
But,as compared with the other three statements,it is the only statement which speaks against the good nature of the ground water.