Which of the following metals has the largest abundance in the earth's crust? 

• Aluminium

• Calcium

• Magnesium

• Sodium

For which element the inertness of the electron pair will not be observed? 

• Sn

• Fe

• Pb

• In

Radioactivity of a sample (Z = 22) decreases 90% after 10 yr. What will be the half-life of the sample? 

• 5 yr

• 2 yr

• 3 yr

• 10 yr

Vitamin C is

• citric acid

• lactic acid

• paracetamol 

• ascorbic acid

Keto - enol tautomerism is not observed in

• C₆H₅COC₆H₅

• C₆H₅COCH=CH₂

• C₆H₅COCH₂COCH₃

• CH₃COCH₂COCH₃

Boiling water reacts with C₆H₅N${}_2^{+}$Cl^- to give

• aniline

• benzylamine

• phenol

• benzaldehyde

37.

X $\stackrel{{\mathrm{PCl}}_5}{\to }$ C₂H₅Cl, Y $\stackrel{{\mathrm{PCl}}_5}{\to }$ CH₃COCl

X and Y are

• (C₂H₅)₂O and CH₃CO₂H

• C₂H₅I and C₂H₅CHO

• C₂H₅OH and CH₃CO₂H

• C₂H₅OH and C₂H₅CHO

When AgCl is treated with KCN

• Ag is precipitated

• a complex ion is formed

• double decomposition takes place

• no reaction takes place

Which one of the following produced when acetone is saturated with HCl gas?

• Acetone alcohol

• Phorone

• Mesityl oxide

• Benzene

Which one of the following is an example of co-polymer?

• Buna-S

• Teflon

• PVC

• Polypropylene