Which one of the following reactions does not occur?

• F₂ + 2Cl^- → 2F^- + Cl₂

• Cl₂ + 2F^- → 2Cl^- + F₂

• Br₂ + 2I^- → 2Br^- + I₂

• Cl₂ + 2Br^- → 2Cl^- + Br₂

The formula of the product formed, when sodium thiosulphate solution is added to silver bromide is

• Ag₂S₂O₃

• Ag₂S

• Na₃[Ag(S₂O₃)₂]

• Ag₃[Na(S₂O₃)₂]

Which one of the following noble gases is used in miner's cap lamps ?

• Helium

• Neon

• Argon

• Krypton

The following are some statements related to VA group hydrides,

(I) Reducing property increases from NH₃ to BiH₃

(II) Tendency to donate lone pair decreases from NH₃ to BiH₃.

(III) Thermal stability of hydrides decreases from  NH₃ to BiH₃.

(IV). Bond angle of hydrides decreases from  NH₃ to BiH₃.

The correct statements are:

• I, II, III and IV

• I, III and IV

• L, II and IV

• I and IV

The type of bonds present in sulphuric anhydride are

• 3σ and three p$\mathrm{\pi }$-d$\mathrm{\pi }$

• 3σ and one p$\mathrm{\pi }$-p$\mathrm{\pi }$ and two p$\mathrm{\pi }$-d$\mathrm{\pi }$

• 2σ and three p$\mathrm{\pi }$-d$\mathrm{\pi }$

• 2σ and two p$\mathrm{\pi }$-d$\mathrm{\pi }$

Which pair of oxyacids of phosphorus contains 'P-H' bonds?

• H₃PO₄, H₃PO₃

• H₃PO₅, H₄P₂O₇

• H₃PO₃, H₃PO₂

• H₃PO₂, HPO₃

The made of nitrogen formed by thermal decomposition of NH₄NO₃ is

• NO

• N₂O

• N₂O₅

• NO₂

Which one of the following is most acidic?

• H₂O

• H₂S

• H₂Te

• H₂Se

149.

Which one of the following is formed apart from sodium chloride when chlorine reacts with hot concentrated sodium hydroxide?

• NaOCl

• NaClO₃

• NaClO₂

• NaClO₄

Helium mixed with oxygen is used in the treatment of

• beri beri

• burning feet

• joints burning

• asthma