Question 1

The effect of hydrogen bonding on λmax is------------------

Accepted Answer

Bathochromic shift

Answer

Hypsochromic shift

Answer

Hypochromic shift

Answer

Hyperchromic shift

Question 2

Aqueous solution of mesityl oxide shows two absorption peaks at λmax 305 and 243 nm in its UV spectrum. Identify the type of transition

Accepted Answer

n- π*,π-π*,

Answer

π-π*, n-σ*

Answer

π-π*, n- π*

Answer

σ- σ*, n- π*

Question 3

The λmax values of the following compounds are 242 nm, 254 nm and 259 nm in ethanol. Which is which?

Accepted Answer

A-259 nm B- 242 nm C-254 nm

Answer

A- 259 nm B- 254 nm C-242 nm

Answer

A-249 nm B- 242 nm C-259 nm

Answer

A-242 nm B- 259 nm C-254 nm

Question 4

The position of UV absorption maxima of aniline in aqueous solution are different from those of benzene but those of aniline in an acidic aqueous solution at pH=1 are almost identical with those of benzene. Pick out the reasons

Accepted Answer

All the above

Answer

Both the bands K and B bands are shifted to longer wavelength in aqueous medium

Answer

In acidic solution, protonation occurs at the lone pair of N atom.

Answer

lone pair of electrons on N atom in aniline spread into benzene ring due to resonance

Question 5

In UV Visible spectrum of α, β Unsaturated carbonyl compounds, with increasing polarity

Accepted Answer

n-π* transitions show hypsochromic and π-π* transitions show bathochromic shifts

Answer

both transitions undergo hypsochromic

Answer

both transitions undergo bathochromic

Answer

n-π* transitions show bathochromic and π-π* transitions show hypsochromic shifts

Question 6

Calculate absorption maxima

Accepted Answer

282 nm

Answer

278 nm

Answer

252 nm

Answer

302 nm

Question 7

For electronic transitions in organic molecules the expected energy ordering of the transition

Accepted Answer

n- π*< π-π*< n-σ*< σ- σ*

Answer

π-π*<

Answer

n-σ*< σ- σ*< n- π*< π-π*

Answer

π-π*<n-σ*<σ- σ*<n- π*

Question 8

Identify the correct statement regarding auxochrome

Accepted Answer

Both B and C

Answer

Auxochromes are substances which absorb UV and visible light radiations and impart colour to the compound

Answer

hydroxyl group is an eg for auxochrome

Answer

Groups that increase the absorption value

Question 9

How many exocyclic double bonds in this organic compound?

Accepted Answer

3

Answer

0

Answer

2

Answer

1

Question 10

Calculate absorption maxima

Accepted Answer

281 nm

Answer

268 nm

Answer

218 nm

Answer

286 nm

Related quizzes

Related quizzes