p-Block Elements Test - 12

Sulphuric acid has four highly polar ends which means it can form strong hydrogen bonds with water at those sites. There are two O-H bonds which can easily hydrolyse. The equilibrium for the below reaction lies far to the right:

H₂SO₄ + H₂O → HSO⁻₄ + H₃O⁺

Thus, the hygroscopic nature of H₂SO₄ contributes to its spontaneous overflow.

All are correctly matched.
(A) Hypo is used to remove iodine stains as it reacts with I₂ as follows:
2Na₂S₂O₃ + I_{2 →} Na₂S₄O₆ + 2NaI
(B) 5CO + I₂O₅ → 5CO₂ + I₂
(C) CuSO₄ + 2KI → CuI + I₂ + K₂SO₄
The CuI formed is brown in colour.
(D) Glass contains silicon oxides and silicon has a great affinity for F^-; therefore, glass dissolves in HF.
Hence, all the options are correctly matched.

Cl₂ + 2NaOH → NaCl + NaOCl + H₂O for cold NaOH
3Cl₂ + 6NaOH → 5NaCl + NaClO₃ + 3H₂O for hot NaOH
Chlorine is oxidized much more strongly with hot NaOH than cold.
Cl₂ starts as neutral and becomes +1 in NaOCl.
Cl₂ starts as neutral and becomes +5 in NaClO_3.
The hot and concentrated NaOH is a stronger oxidizing agent than cold dilute NaOH.

The statements (A), (B) and (C) are correct.
The Cl-O bond length is the minimum and bond energy is the maximum in ClO₄^-.
Hence, the statement (D) is incorrect.

Helium is used as a cooling medium for the Large Hadron Collider (LHC) and the superconducting magnets in MRI scanners and NMR spectrometers. It is also used to keep satellite instruments cool and was used to cool the liquid oxygen and hydrogen that powered the Apollo space vehicles.