Question

Correct statement(s) is/are:

• A. Diamond has more thermal conductivity than graphite
• B. 1 mol of $M{g}_2{C}_3$ reacts with water to give 3 mol of $C_3{H}_4$ gas
• C. The order of the lewis acidic strength is: $B{F}_3>BC{l}_3>BB{r}_3$
• D. Aqueous solution of borax is basic in nature

Answer 1

Answer: (A), (D)

Aqueous solution of borax is basic in nature

a) Diamond has more thermal conductivity than graphite.
b) $M{g}_2{C}_3+4H_{2}O⟶2Mg(OH{)}_2+C_3{H}_4$
So 1 mol of $M{g}_2{C}_3$ reacts with water to give 1 mol of $C_3{H}_4$.
c) The order of the Lewis acidic strength is: $B{F}_3<BC{l}_3<BB{r}_3$. This is because of back bonding. As the side atom gets bigger, the orbital overlap with boron decreases. So, the extent of back bonding decreases and so does the electron deficit on boron.
d) Chemical formula of borax is $N{a}_2\left[B_4{O}_5\right(OH{)}_4].8H_{2}O$. Thus, it is a salt of $NaOH$ (strong base) and $H_{3}B{O}_3$ (weak acid). So, aqueous solution of borax is basic in nature.