31.

Iron exhibits bcc structure at room temperature. Above 900°C, it transforms to fcc structure. The ratio of density of iron at room temperature to that at 900°C (assuming molar mass and atomic radii of iron remains constant with temperature) is

• $\frac{\sqrt{3}}{\sqrt{2}}$

• $\frac{4\sqrt{3}}{3\sqrt{2}}$

• 1/2

• $\frac{3\sqrt{3}}{4\sqrt{2}}$

Consider the following species:
CN⁺, CN^–, NO and CN

Which one of these will have the highest bond order?

• NO

• CN^-

• CN

• CN⁺

The correct order of N-compounds in its decreasing order of oxidation states is

• HNO₃, NH₄Cl, NO, N₂

• HNO₃, NO,NH₄Cl, N₂

• HNO₃, NO, N₂, NH₄Cl

• NH₄Cl, N₂, NO, HNO₃

Identify the major products P, Q and R in the following sequence of reactions:

Which of the following compounds can form a zwitter ion?

• Aniline

• Acetanilide

• Glycine

• Benzoic acid

Regarding cross-linked or network polymers, which of the following statements is incorrect?

• They contain covalent bonds between various linear polymer chains.

• They are formed from bi- and tri-functional monomers.

• They contain strong covalent bonds in their polymer chains.

• Examples are bakelite and melamine.

Nitration of aniline in strong acidic medium also gives m-nitroaniline because

• Inspite of substituents nitro group always goes to only m-position.

• In electrophilic substitution reactions amino group is meta directive.

• In acidic (strong) medium aniline is present as anilinium ion.

• In absence of substituents nitro group always goes to m-position.

The difference between amylose and amylopectin is

• Amylopectin have 1 → 4 α-linkage and 1 → 6 α-linkage

• Amylose have 1 → 4 α-linkage and 1 → 6 β-linkage

• Amylose is made up of glucose and galactose

• Amylopectin have 1 → 4 α-linkage and 1 → 6 β-linkage

The compound A on treatment with Na gives B, and with PCl₅ gives C. B and C react together to give diethyl ether. A, B and C are in the order

• C₂H₅OH, C₂H₆, C₂H₅Cl

• C₂H₅OH, C₂H₅Cl, C₂H₅ONa

• C₂H₅OH, C₂H₅ONa, C₂H₅Cl

• C₂H₅Cl, C₂H₆, C₂H₅OH

The compound C₇H₈ undergoes the following reactions:

The product 'C' is

• m-bromotoluene

• o-bromotoluene

• p-bromotoluene

• 3-bromo-2,4,6-trichlorotoluene