Page 84 - Chemistry - XI

Assertion-Reason Type Questions

These consist of two statements–Assertion (A) and Reason (R). Answer these questions by selecting the

appropriate option given below:
a. Both A and R are true and R is the correct explanation of A.
b. Both A and R are true and R is not the correct explanation of A.

c. A is true, but R is false. d. A is false, but R is true.
1. Assertion (A) : Cations of both Cu (II) group and Fe (III) group are precipitated by passing H S
2
gas, but former in dilute acidic medium while later in dilute alkaline medium.
Reason (R) : Sulphides of Cu (II) group cations have lower solubility than that of Fe (III) group
cations.

2. Assertion (A) : Ca and Ba can be distinguished by treatment with Na C O solution.
2+
2+
2 2 4
Reason (R) : CaC O is soluble in dilute acetic acid while BaC O is insoluble in dilute acetic
2
4
4
2
acid solution.
3. Assertion (A) : Borax bead test is applicable only to coloured salt.
Reason (R) : In borax bead test, coloured salts are decomposed to give coloured metal meta
borates.
4. Assertion (A) : Sulphide gives purple colour with sodium nitroprusside solution.
Reason (R) : Sodium nitroprusside is a complex compound.

5. Assertion (A) : Phosphates are identifi ed by the yellow precipitate obtained on adding ammonium
molybdate solution.
Reason (R) : Ammonium phosphomolybdate is a yellow compoud.

6. Assertion (A) : Boiling a solution containing Cl , Br , and I with potassium persulphate, violet
–
–
–
and brown vapours appear.
Reason (R) : Br and I are oxidised to Br and I and Cl is not oxidised.
–
–
–
2 2
7. Assertion (A) : Chloride is confi rmed by chromyl chloride test.
Reason (R) : Chlorine is evolved when Chloride is heated with conc. H SO .
2 4
8. Assertion (A) : Cu and Cd are separated by fi rst adding KCN solution and then passing H S gas
2+
2+
2
Reason (R) : KCN reduces Cu to Cu and forms a complex with it.
+
2+
9. Assertion (A) : CdS and As S both have yellow colour and precipitated by passing H S through
2
2 3
solution in dil HCl.
Reason (R) : Both can be separated by yellow ammonium sulphide.
10. Assertion (A) : PbCl and HgCl precipitates can be separated by hot water.
2 2
Reason (R) : Aqueous PbCl gives yellow ppt. with K CrO solution.
2
4
2
Answer key

1. (a), 2. (c), 3. (a), 4. (b), 5. (a), 6. (b), 7. (c), 8. (a), 9. (b), 10. (b)1. (a), 2. (c), 3. (a), 4. (b), 5. (a), 6. (b), 7. (c), 8. (a), 9. (b), 10. (b)

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