Question

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.

पर्याय

• Statement I is false but statement II is true.

• Statement I is true but Statement II is false.

• Both Statement I and Statement II are true.

• Both Statement I and Statement II are false.

Answer 1

Both Statement I and Statement II are false.

Explanation:

Copper metaborate is transparent green when hot and transparent blue when cold in non-luminous flame.

\[\ce{2CuSO4 -> 2CuO + 2SO2 + O2}\]

\[\ce{CuO + B2O3 -> \underset{Copper metaborate}{2Cu(BO2)2}}\]

In reducing flame i.e., in a luminous flame, the bead becomes opaque red.

\[\ce{2Cu(BO2)2 + C -> Cu2(BO2)2 + B2O3 + CO}\]

\[\ce{Cu2(BO2)2 + C -> 2red Cu + B2O3 + CO}\]