Given below are two statements :
Statement I: Upon heating a borax bead dipped in cupric sulphate in a luminous flame, the colour of the bead becomes green.
Statement II : The green colour observed is due to the formation of copper(I) metaborate.
In the light of the above statements, choose the most appropriate answer from the options given below :
Statement I: Upon heating a borax bead dipped in cupric sulphate in a luminous flame, the colour of the bead becomes green.
Statement II : The green colour observed is due to the formation of copper(I) metaborate.
In the light of the above statements, choose the most appropriate answer from the options given below :
- (A)Both Statement I and Statement II are true
- (B)Statement I is true but Statement II is false
- (C)Both Statement I and Statement II are false✓ Correct
- (D)Statement I is false but Statement II is true
Answer: (C)
Solution
In the borax bead test a copper salt gives its characteristic blue-green bead only in the oxidising, non-luminous flame, where cupric metaborate is formed. Held in the luminous, reducing flame the bead turns colourless, from cuprous metaborate, or red and opaque from metallic copper, so it does not become green there, and the first statement is false. The green colour, where it does appear, belongs to copper(II) metaborate and not to a copper(I) species, so the second statement is false as well. Both statements are false.
JEE Main · 2023 · 31 Jan 2023 · Shift 2 · Single correct option