Assertion: When air is passed through lime water, lime water turns milky. Reason: Air contains 78% nitrogen and 21% oxygen.
Answers
Answer:
When carbon dioxide is passed through lime water for a short time,it turns lime water milky due to formation of a white precipitate of calcium carbonate. Exhaled air contains less oxygen and more carbon dioxide. ... So the correct answer is 'Carbon dioxide'.
hope you get the answer
Answer:
Option B. Both A and R are true, but R is not the correct explanation of A.
Explanation:
Dissolved Carbon dioxide (CO2) reacts with the lime-water, Ca(OH)2 solution to form a white precipitate which shows a milky appearance due to the formation of Calcium carbonate, CaCO3.
The addition of more carbon dioxide leads to the dissolving of the precipitate, forming a colourless solution of calcium hydrogen-carbonate, Ca(HCO3).
The below reactions explains the formation of calcium carbonate precipitate which gives a milky appearance:
Ca(OH)2 + CO2 → CaCO3 + H2O
CaCO3 + CO2 + H2O(l) → Ca(HCO3)2
Lime Water solution is used as a test to detect the presence of carbon dioxide. The unknown gas sample is passed through the calcium carbonate solution. If it contains carbon dioxide it turns milky.
The assertion is True: When the air is passed through the lime water, lime water turns milky.
The reason is not the correct explanation: Other than 78% nitrogen and 21% oxygen, air also contains 0.04% carbon dioxide. The lime-water solution only reacts with carbon dioxide gas.
Option (B) is the correct answer.
Question:
The correct question should be:
Assertion: When air is passed through lime water, lime water turns milky. Reason: Air contains 78% nitrogen and 21% oxygen.
A. Both A and R are true and R is the correct explanation of A.
B. Both A and R are true, but R is not the correct explanation of A.
C. A is true, but R is false.
D. A is false, but R is true.
E. Both A and R are false.