Question

When strongly heated, orthoboric acid gives
a) HBO₂
b) H₂B₄O₇
c) B₂O₃
d) B

Answer 1

Dear Dhanush,

● Answer -

When strongly heated, orthoboric acid gives boric oxide (B₂O₃).

● Reaction -

Orthoboric acid (H₃BO₃) when heated gives metaboric acid (HBO₂).

H₃BO₃ + ∆ → HBO₂

On further strong heating, metaboric acid (HBO₂) gives boric oxide (B₂O₃).

HBO₂ + ∆ → B₂O₃

* This reaction takes place at 370 ℃.

Hope this helps you gain more knowledge. Thanks for asking..

Answer 2

Answer:

The correct answer option is a) HBO₂.

Explanation:

When orthoboric acid is strongly heated (on a temperature above 170° C), it gives metaboric acid which has the formula HBO₂.

$H _ 3 B O _ 3 \implies H B O _ 2 + H _ 2 O$

While on further heating it (above 300°C), it gives tetraboric acid (H₂B₄O₇).

$4HBO_2 \implies H_2B_4O_7 + H_2O$