Chemistry
Assertion (A): Granulated zinc is preferred over pure zinc in the preparation of hydrogen using dilute acids.
Reason (R): Granulated zinc contains traces of impurities which have a slight catalysing effect on the reaction.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Answer
Both A and R are true and R is the correct explanation of A.
Explanation — Zinc granules are preferred for preparation of hydrogen over pure zinc because the impurity present in granulated zinc is copper, whose catalysing effect speeds up the rate of reaction. Hence both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
Related Questions
Assertion (A): Though hydrogen is lighter than air, it is not collected by the downward displacement of air but by the downward displacement of water.
Reason (R): Hydrogen is slightly soluble in water.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Assertion (A): Hydrogen and alkali metals react with a black copper oxide to give red/brown copper.
Reason (R): Hydrogen and alkali metals are good oxidising agents.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Assertion (A): In Bosch process, hydrogen and carbon dioxide are formed.
Reason (R): Hydrogen and carbon dioxide are separated by passing through ammoniacal cuprous chloride solution.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Assertion (A): While preparing hydrogen in laboratory, no leakage of gas should take place and no flame must be present near the apparatus.
Reason (R): Hydrogen-air mixture burns with a characteristic pop sound.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.