Which one of the following has the shortest bond length?

• C - H

• C - N

• C - F

• C - C

Pick out the wrong statement.

• Nitrogen has the ability to form p$\mathrm{\pi }$-p$\mathrm{\pi }$ bonds with itself

• Bismuth forms metallic bonds in elemental state

• Catenation tendency is higher in nitrogen when compared with other elements of the same group

• Nitrogen has higher first ionization enthalpy when compared with other elements of the same group

393.

The wrong statement about the interstitial compounds is

• their melting points are lower than those of pure metals

• they retain metallic conductivity

• they are chemically inert

• their bonds are neither ionic non covalent

Which of the following is not correct with respect to bond length of the species? 

• C₂ > ${\mathrm{C}}_2^{2-}$

• ${\mathrm{B}}_2^{+}$ > B₂

• ${\mathrm{Li}}_2^{+}$ > Li₂

• O₂ > O${}_2^{-}$

Substance which is weakly repelled by a magnetic field is

• O₂

• H₂O

• CrO₂

• Fe₃O₄

The bonds present in the structure of dichromate ion are

• four equivalent Cr-O bonds only

• six equivalent Cr-O bonds and one Cr - O - O bond

• six equivalent Cr-O bonds and one O-O bond

• eight equivalent Cr-O bonds

Which of the following statements is false?

• H₂  molecule has 1σ bond 

• Acetylene molecule has 3σ bonds and 3Π bonds

• HCl molecule has 1σ bond

• Water molecule has 2σ bonds and two lone pairs

N₂ and O₂ are converted to monopositive cation ${\mathrm{N}}_2^{+}$ and ${\mathrm{O}}_2^{+}$respectively. Which is incorrect?

• In ${\mathrm{N}}_2^{+}$, the N-N bond weakened.

• In ${\mathrm{O}}_2^{+},$ the bond order increases

• In ${\mathrm{O}}_2^{+},$ paramagnetism decreases

• ${\mathrm{N}}_2^{+}$  becomes diamagnetic

A netural molecule XF₃ has a zero dipole moment. The element X is most likely

• chlorine

• boron

• nitrogen

• carbon

The stablest radical among the following is

• C₆H₅ - CH₂ - $\stackrel{.}{\mathrm{C}}$H₂

• CH₃$\stackrel{.}{\mathrm{C}}$H₂

• C₆H₅ - $\stackrel{.}{\mathrm{C}}$H₂-CH₃

• CH₃-$\stackrel{.}{\mathrm{C}}$H-CH₃