Question

Which of the following statements is false for the addition of H-Cl to 1,3-butadiene at 42 degrees C results in the following products:

The minor product results from a resonance structure and is the 1,4-product.

1-chloro-2-butene and 1-chloro-3-butene are formed.

The major product has E/Z isomerism

Both products do not contain a stereogenic center.

b)Which of the following is false as it pertains chemical shift (delta, ppm) in proton NMR spectroscopy:

The chemical resonance that appears furthest upfield for the choices of CHCl3, CH2Br2, and CH3F is CH2Br2.

The aldehydic H (H attached to the C of the C=O) is shifted between 9 – 10 ppm.

For primary, secondary, and tertiary carbons, the chemical resonance shifts downfield.

Aromatic hydrogens are shifted to downfield with respect to vinyl Hs (HC=).

c)The CH2 hydrogens on C2 of cis 1-chloro-4-iodocyclohexane are:

Homotopic

Enantiotopic

Diastereotopic

Stereotopic

Answer 1

a) the addition of HCl with 1,3-butadiene it forms 70 % yield of 3-chloro-1-butene and 30% yield of 1-chloro-3-butene formed at 42^oC

the major product 3-chloro-1-butene has E/Z isomerism.

hence form the above discussion the false statement is option-4

i.e, Both products donot contain a stereogenic centre.

b) the false statement is option-1

i.e, the chemical resonance that appears furthest upfield for the choices of CHCl3,CH2Br2, and CH3F is CH2Br2

c) The CH2 hydrogens on C2 of cis-1-chloro-4-iodocyclohexane are: Enantiotopic