Download App

The p-Block Elements — Chemistry STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceChemistryThe p-Block Elements2 Marks
Question
$\mathrm{BCl}_3$ exists but $\mathrm{BH}_3$ does not. Explain.
✓

Answer

In $\mathrm{BCl}_3, \mathrm{Cl}$ donates lone pair of electrons to vacant p-orbital of boron (back-bonding) making it more stable whereas in $\mathrm{BH}_3$ back-bonding is not possible, therefore, it exists as dimer. Secondly, in $\mathrm{BCl}_3$, chlorine being bigger in size cannot form bridged bonds like hydrogen in $\mathrm{B}_2 \mathrm{H}_6$.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "2 Marks Questions" from The p-Block Elements→The p-Block Elements — all question types→Chemistry STD 11 Science question papers→Gujarat Board STD 11 Science question papers→Gujarat Board question paper generator→

Similar questions

What mass of silver nitrate will react with 5.85g of sodium chloride to produce 14.35g of silver chloride and 8.5g of sodium nitrate, if the law of conservation of mass is true?
→
Name the species that will be isoelectronic with the following atoms or ions:
i. $Na$
ii. $\mathrm{Cl}^{-}$
iii. $\mathrm{Ca}^{2+}$
iv. $\mathrm{Rb}^{+}$
→
Atomic number (Z) of an element is 108. Write its electronic configuration and name the group and block to which it belongs.
→
6.8 gm NaOH is dissolved in water to prepare
2 litre solution, then calculate pH of solution.
→
In three moles of ethane ($\mathrm{C}_2 \mathrm{H}_6$), calculate the following:
Number of moles of hydrogen atoms.
→
Draw the gas phase and solid phase structure of $\text{H}_2\text{O}_2$.
→
A solution of silver nitrate was stirred with iron rod. Will it cause any change in the concentration of silver and nitrate ions?
→
At what temperature the solid and liquid are in equilibrium under 1 atm pressure?
→
Identify (A), (B), (C) and (D) and give their chemical formulae.
$\text{(A)}+\text{NaOH}\xrightarrow{\ \\ \ \ \\ \ \ \\ \ \ }\text{NaCl}+\text{NH}_3+\text{H}_2\text{O}$
$\text{(B)}+\text{NaCl}\xrightarrow{\ \\ \ \ \\ \ \ \\ \ \ }\text{(C)}+\text{NH}_4\text{Cl}$
$\text{(C)}\xrightarrow{\text{Heat}}\text{Na}_2\text{CO}_3+\text{H}_2\text{O}+\text{(D)}$
→
What happens when
  1. Calcium phosphide is hydrolysed
  2. Ammonia reacts with water
→