21.

Among the following the aromatic compound is

• 

• 

• 

• 

The geometrical isomerism is shown by

Ozone in stratosphere is depleted by

• CF₂Cl₂

• C₇F₁₆

• C₆H₆Cl₆

• C₆F₆

Assertion: Mg is not present in enamel of human teeth.

Reason : Mg is an essential element for biological functions of human.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false.

Assertion : Styrene on reaction with HBr gives 2-bromo-2-phenyl ethane.

Reason: Benzyl radical is more stable than alkyl radical.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If resason is true but assertion is false

• If both assertion and reason are false.

Assertion : The pK_a of acetic acid is lower than that of phenol.

Reason : Phenoxide ion is more resonance stabilised

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false.

Assertion : Alcohols are dehydrated to hydrocarbons in the presence of acidic zeolites.

Reason : Zeolites are porous catalysts.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false.

Which one ofthe following forms with an excess of CN^- (cyanide) a complex having coordination number two?

• Cu⁺

• Ag⁺

• Ni²⁺

• Fe²⁺

Which of the following is not considered as an organometallic compound?

• cis-Platin

• Ferrocene

• Zeise's salt

• Grignard reagent

The element which forms oxides in all oxidation states +I to +V is

• N

• P

• As

• Sb