Question

$H_{3}B{O}_3\stackrel{T_1}{\to }X\stackrel{T_2}{\to }Y\stackrel{redhot}{\to }{B}_2{O}_2$

if $T_1<T_2$ then X and Y respectively are-

• A. $X=$ Metaboric acid and $Y=$ Tetraboric acid
• B. $X=$ Tetraboric acid and $Y=$ Metaboric acid
• C. $X=$ Borax and $Y=$ Metaboric acid
• D. $X=$ Tetraboric acid and $Y=$ Borax

Answer 1

The correct option is A $X=$ Metaboric acid and $Y=$ Tetraboric acid

Effect of temperature at ${100}^{\circ }C,H_{3}B{O}_3$ losses water and convert into metaboric acid.

$H_{3}B{O}_3\stackrel{{100}^{\circ }C}{\to }HB{O}_2+H_{2}O$

metaboric acid form tetraboric acid on heating at ${160}^{\circ }C$

$4HB{O}_2\stackrel{{160}^{\circ }C}{\to }{H}_2{B}_4{O}_7+H_{2}O$

On strong heating, $B_2{O}_3$ is produced

$H_2{B}_4{O}_7\to 2B_2{O}_3+H_{2}O$

Hence, option $A$ is correct.