Given below are two statements :
Statement I : Colourless cupric metaborate is reduced to cuprous metaborate in a luminous flame.
Statement II : Cuprous metaborate is obtained by heating boric anhydride and copper sulphate in a non-luminous flame.
In the light of the above statements, choose the most appropriate answer from the options given below.
Statement I : Colourless cupric metaborate is reduced to cuprous metaborate in a luminous flame.
Statement II : Cuprous metaborate is obtained by heating boric anhydride and copper sulphate in a non-luminous flame.
In the light of the above statements, choose the most appropriate answer from the options given below.
- (A)Statement I is false but statement II is true.
- (B)Statement I is true but Statement II is false.
- (C)Both Statement I and Statement II are true.
- (D)Both Statement I and Statement II are false.✓ Correct
Answer: (D)
Solution
Both statements are false.
Analysis:
Statement I is false because:
Statement II is false because:
The correct chemistry:
(Blue colored cupric metaborate)
(Blue cupric metaborate is reduced to metallic copper)
Therefore, both statements contain errors and are false.
Analysis:
Statement I is false because:
- Cupric metaborate is blue colored, not colorless
- It is the cupric metaborate that is reduced to copper metal (not cuprous metaborate) in a luminous (reducing) flame
Statement II is false because:
- Cupric metaborate (not cuprous) is obtained by heating boric anhydride with copper sulfate
- This reaction occurs in a non-luminous (oxidizing) flame, which is correct
- But the product is cupric metaborate, Cu(BO₂)₂, which is blue colored
The correct chemistry:
- In a non-luminous (oxidizing) flame:
(Blue colored cupric metaborate)
- In a luminous (reducing) flame:
(Blue cupric metaborate is reduced to metallic copper)
Therefore, both statements contain errors and are false.
JEE Main · 2021 · 24 Feb 2021 · Shift 1 · Single correct option