Name: Understanding Silicate and Its Uses
Uploaded: 2019-07-19
Duration: 9 min 26 s
Description: Do you know that silicates are used to make glass and ceramics? It also plays a vital role in our daily life. Let's learn how it simplifies our lives.

Question

State with equations what happens when borax is heated on a platinum wire loop and to the resulting transparent mass, a minute amount of

CuO

is added and the mixture is again heated first in the oxidising flame, and then in the reducing flame of a Bunsen burner?

Accepted Answer

When borax is heated on a platinum wire loop, a transparent glassy bead-like compound is formed.

${Na}_{2} B_{4} O_{7} . 10 H_{2} O \to_{- 10 H_{2} O}^{heat} {Na}_{2} B_{4} O_{7} \to_{}^{Heat} \underset{Transparent Glass bead}{2 {NaBO}_{2} + B_{2} O_{3}}$

The transparent glassy bead is heated with $CuO$ in the oxidizing flame, it imparts a blue colour to the bead due to the formation of Cupric Metaborate $[Cu {({BO}_{2})}_{2}]$ .

However, when cupric metaborate is heated in the reducing flame of the Bunsen burner, the blue cupric metaborate is reduced by carbon present in the flame first to colourless cuprous metaborate $({CuBO}_{2})$ .

$[Cu {({BO}_{2})}_{2}] + C \to 2 {CuBO}_{2} + B_{2} O_{3} + CO$

Now, when it is reduced to metal $(Cu)$ which produces a red colour.

${CuBO}_{2} + C \to Cu + B_{2} O_{3} + CO$

State with equations what happens when borax is heated on a platinum wire loop and to the resulting transparent mass, a minute amount of $CuO$ is added and the mixture is again heated first in the oxidising flame, and then in the reducing flame of a Bunsen burner?

Important Questions on The p-Block Elements

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