In the nitrogen family the H-M-H bond angle in the hydrides (MH₃ ) gradually becomes closer to 90° on going from N to Sb. This shows that

• the basic strength of hydrides increases

• the bond energies of M-H bonds increases

• almost pure p-orbitals are used for M-H bonding

• the bond pairs of electrons come nearer to the central atom

Which of the following, on heating with ammonia gives urotropin?

• Formaldehyde

• Acetaldehyde

• Acetone

• Benzaldehyde

Which one of the following will give a white precipitate with AgNO₃ in aqueous medium?

• [Co(NH₃)₂Cl] (NO₂)₂

• [Pt(NH₃)₂Cl₂]

• [Pt(en) Cl₂]

• [Pt(NH₃)₄]Cl₂

Which one of the following sulphide is yellow?

• Zinc sulphide

• Cadmium sulphide

• Nickel sulphide

• Lead sulphide

In the mixture of conc. H₂SO₄ and HNO₃ the nitration species is

• N₂O₄

• NO₂⁺

• NO₂

• NO₂^-

A mixture containing Cu²⁺ and Ni²⁺ can be separated for identification by

• passing H₂S in acid medium

• passing H₂S in alkaline medium

• passing H₂S in neutral medium

• passing H₂S in dry mixture

Chlorine cannot displace

• fluorine from NaF

• iodine from NaI

• bromine from NaBr

• None of the above

The electronic configuration of an element is 1s²,2s² 2p⁶, 3s² 3p⁶, 3d¹⁰, 4s² 4p³. To which of the following elements it is similar in properties?

• Boron

• Oxygen

• Nitrogen

• Chlorine

Which of the following will replace Br₂ from the aqueous solution having bromide ion?

• Cl₂

• I${}_3^{⊝}$

• I₂

• Cl^{${}^{⊝}$}

390.

In which of the following compound the oxidation number of oxygen is +2?

• H₂O₂

• CO₂

• H₂O

• OF₂