Which of the following forms holes in the ozone layer?

• CO

• SO₂

• CO₂

• CF₂Cl₂

To prepare XeF₆. Xe and F₂ are mixed at 573 K and 60-70 bar in the ratio of

• 20:1

• 1:5

• 5:1

• 1:20

In which of the following reactions, hydrogen is liberated?

$$\begin{gathered} \left(\mathrm{i}\right) \mathrm{Al}\left(\mathrm{s}\right) + \mathrm{HCl}\left(\mathrm{aq}\right) \to \\ \left(\mathrm{ii}\right) \mathrm{Al} \left(\mathrm{s}\right) +\hspace{0.17em}\mathrm{NaOH}\left(\mathrm{aq}\right)\hspace{0.17em}\to \\ \left(\mathrm{iii}\right) {\mathrm{NaBH}}_4 + {\mathrm{I}}_2 \to \end{gathered}$$

• i, ii

• ii, iii

• i,iii

• i, ii, iii

Two oxides of an non-metal X contain 50% and 40% of non-metal respectively. If the formula of the first oxide is XO₂. Then the formula of second oxide is

• X₂O₃

• X₂O₅

• XO₃

• X₂O

S + Conc. H₂SO₄ → X + Y 

Here X is a gas and Y is a liquid and both are triatomic molecules. The number of electron lone pairs present on the central atoms of X and Y are respectively.

• 2,1

• 1,0

• 1,2

• 2,2

Which of the following is used in estimation of carbon monoxide?

• I₂O₄

• BrO₃

• Cl₂O₇

• I₂O₅

367.

Which one ofthe following statements is not correct?

• In CO₂ molecule, carbon hybridisation is sp

• Fullerenes are made by heating graphite in an electric are in the presence of argon gas

• Both [SiF₆]^2- and [SiCl₆]^2- ions are known

• In CO molecule, there are one 'sigma' and two "pi" bonds

Which of the following is the anhydride of nitric acid?

• NO

• NO₂

• N₂O₃

• N₂O₅

Chlorine atom differs from chloride in the number of which of the following?

• Protons

• Neutrons

• Electrons

• Both (a) and (c)

In the following reaction,

P₄ + 3NaOH + 3H₂O → PH₃ + 3NaH₂PO₂

• phosphorus is oxidised

• phosphorus is oxidised and reduced

• phosphorus is reduced

• sodium is oxidised