The correct statement about the S_N1 reaction is:

1.	100 % racemisation.
2.	Inversion more than retention leads to partial racemisation.
3.	100 % retention.
4.	100 % Inversion.

Two possible stereo-structures of CH₃CHOH.COOH, that are optically active, called:

In which of the following compounds, the C—Cl bond ionization shall give the most stable carbonium ion?

1.		2.
3.		4.

The enolic form of ethyl acetoacetate is given below-

 

The number of σ and π bonds in the enolic form are respectively:

1. 18 sigma bonds and 2 pi-bonds
2. 16 sigma bonds and 1 pi-bond
3. 9 sigma bonds and 2 pi-bonds
4. 9 sigma bonds and 1 pi-bond

The structure of the compound whose IUPAC name is 3-Ethyl-2-hydroxy-4-methylhex-3-en-5-ynoic acid is:

1.		2.
3.		4.

The correct order of increasing bond length of  C-H, C-O, C-C and C=C is:

1.  $\mathrm{C}-\mathrm{C}<\mathrm{C}=\mathrm{C}<\mathrm{C}-\mathrm{O}<\mathrm{C}-\mathrm{H}$

2.  $\mathrm{C}-\mathrm{O}<\mathrm{C}-\mathrm{H}<\mathrm{C}-\mathrm{C}<\mathrm{C}=\mathrm{C}$

3.  $\mathrm{C}-\mathrm{H}<\mathrm{C}-\mathrm{O}<\mathrm{C}-\mathrm{C}<\mathrm{C}=\mathrm{C}$

4.  $\mathrm{C}-\mathrm{H}<\mathrm{C}=\mathrm{C}<\mathrm{C}-\mathrm{O}<\mathrm{C}-\mathrm{C}$

The most reactive compound towards electrophilic reagent among the following is:

1.		2.
3.		4.

The most stable conformation of n-butane among the following is:

1.		2.
3.		4.