Chemistry
Assertion (A): Cold and dilute nitric acid oxidise metals to their nitrates and nitric oxide.
Reason (R): Hot and concentrated nitric acid liberates nitrogen dioxide.
- 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.
Nitric Acid
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Answer
Both A and R are true but R is not the correct explanation of A.
Explanation — Cold and dilute nitric acid oxidises metals to their nitrates and nitric oxide. Hence, the assertion (A) is true.
3Cu + 8HNO3 ⟶ 3Cu(NO3)2 + 4H2O + 2NO
Hot dilute nitric acid or concentrated nitric acid liberates nitrogen dioxide. Hence, the reason (R) is true.
Cu + 4HNO3 ⟶ Cu(NO3)2 + 2H2O + 2NO2
However, reason (R) doesn't explain the action of Cold and dilute nitric acid on metals. So, it is not the correct explanation of assertion (A).
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Related Questions
Assertion (A): The yellow colour of nitric acid is removed by using carbon dioxide gas or dry air.
Reason (R): Carbon dioxide gas or dry air drives away NO2 gas from the warm nitric acid.
- 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): Nitric acid reacts with NaOH/KOH to form salt and water.
Reason (R): Alkalies react with acids to form salt and 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.
Match the following :
Column I Column II (a) A substance which gives off only oxygen when heated. (i) Zinc nitrate (b) A substance which on heating decomposes into nitrous oxide and steam. (ii) Sodium nitrate (c) A substance which gives off oxygen and nitrogen dioxide when heated. (iii) Lead nitrate (d) A substance which on heating leaves yellow residue. (iv) Ammonium nitrate Choose the most appropriate option from the list given below to fill in the blanks.
[NO, Nessler's reagent, NO2, Iron, brown ring, magnesium, Haber's, Ostwald, Iron (II) sulphate, Hydrogen, Iron (III) sulphate](a) A yellow non-metal, sulphur reacts with nitric acid to liberate …………… .
(b) …………… test is used to identify the nitrate radical.
(c) Dilute HNO3 reacts with copper evolving …………… gas.
(d) Nitric acid is obtained on a large scale by the …………… process and the catalyst used is …………… .
(e) In …………… test, freshly prepared …………… solution is used.
(f) Nitric acid in a very dilute form reacts with …………… to form …………… .