21.

Percentages of free space in cubic close packed structure and in body centred packed structure are respectively

• 48% and 26%

• 30% and 26%

• 26% and 32%

• 26% and 32%

Out of the following, the alkene that exhibits optical isomerism is

• 2–methyl–2–pentene

• 3–methyl–2–pentene

• 4–methyl–1–pentene

• 4–methyl–1–pentene

The correct order of E°_M2+/M values with negative sign for the four successive elements Cr, Mn, Fe and Co is

• Cr > Mn > Fe > Co

• Mn > Cr > Fe > Co

• Cr > Fe > Mn > Co

• Cr > Fe > Mn > Co

One mole of a symmetrical alkene on ozonolysis gives two moles of an aldehyde having a molecular mass of 44 u. The alkene is 

• Propene

• 1-butene

• 2-butene

• 2-butene

In the chemical reactions,


the compounds 'A' and 'B' respectively are

• nitrobenzene and fluorobenzene

• phenol and benzene

• benzene diazonium chloride and flurobenzene. 

• benzene diazonium chloride and flurobenzene. 

From amongst the following alcohols the one that would react fastest with conc. HCl and anhydrous ZnCl₂, is

• 1-Butanol

• 2-Butanol

• 2-Methylpropan-2-ol

• 2-Methylpropan-2-ol

Consider the following bromides:



The correct order of S_N1 reactivity is 

• A > B > C

• B > C > A

• B > A > C

• B > A > C

The main product of the following reaction is

Biuret test is not given by 

• proteins

• carbohydrates

• polypeptides

• polypeptides

The polymer containing strong intermolecular forces e.g. hydrogen bonding is

• natural rubber

• Teflon

• Nylon 6,6

• Nylon 6,6