11.

If the first ionization energy of H atom is 13.6 eV, then the second ionization energy of He atom is:

• 27.2 eV

• 40.8 eV

• 54.4 eV

• 108.8 eV

The weight of oxalic acid that will be required to prepare a 1000 ml (N/20) solution is:

• 126/100 g

• 63/40 g

• 63/20 g

• 126/20 g

The paramagnetic behaviour of B₂ is due to the presence of:

• two unpaired electrons in ${\mathrm{\pi }}_{\mathrm{b}}$ MO

• two unpaired electrons in $\stackrel{*}{\mathrm{\pi }}$ MO

• two unpaired electrons in $\stackrel{*}{\mathrm{\sigma }}$ MO

• two unpaired electrons in ${\mathrm{\sigma }}_{\mathrm{b}}$ MO

In 2-butene, which one of the following statements is true?

• C₁-C₂ bond is sp³-sp³ -$\mathrm{\sigma }$-bond

• C₂-C₃ bond is sp³-sp² -$\mathrm{\sigma }$-bond

• C₁-C₂ bond is an sp³-sp² -$\mathrm{\sigma }$-bond

• C₁-C₂ bond is an sp²-sp² -$\mathrm{\sigma }$-bond

The well-known compounds, (+)- lactic acid and (-)- lactic acid, have the same molecular formula, C₃H₆O₃. The correct relationship between them is:

• constitutional isomerism

• geometrical isomerism

• identicalness

• optical isomerism

The stability of Me₂C=CH₂ is more than that of MeCH₂CH=CH₂ due to:

• inductive effect of the Me groups

• resonance effect of the Me groups

• hyperconjugation effect of the Me groups

• resonance as well as the inductive effect of the Me groups

Which one of the following characteristics belong to an electrophile?

• It is any species having electron deficiency which reacts at an electron-rich C-centre

• It is any species having electron enrichment, that reacts at an electron-deficient C-centre

• It is cationic in nature

• It is anionic in nature

When H₂O₂ is shaken with an acidified solution of K₂Cr₂O₇ in the presence of ether, the ethereal layer turns blue due to the formation of:

• Cr₂O₃

• CrO₄^2-

• Cr₂(SO₄)₃

• CrO₅

Friedel-Craft's reaction using MeCl and anhydrous AlCl₃ will take place most efficiently with:

• benzene

• nitrobenzene

• acetophenone

• toluene

Among the following carbocations:

Ph₂C⁺CH₂Me (I), PhCH₂CH₂CH⁺Ph (II), Ph₂CHCH⁺Me (III) and Ph₂C(Me)CH₂ (IV), the order of stability is:

• IV > II > I > III

• I > II > III > IV

• II > I > IV > III

• I > IV > III > II