All categories

3 years ago

Why homoannular diene in uv spectrometry have higher wavlenth than hetroannular diene?

Chemistry

1 answer:

Leno4ka [110]3 years ago

4 0

Answer:

Homoanular dienes have a greater base value than heteroanular dienes

Explanation:

Woodward in 1945 gave a set of rules relating the wavelength of maximum absorption to the structure of a compound. These rules were modified by Fieser in 1959. These sets of rules describe the absorption of organic molecules in the UV region of the electromagnetic spectrum.

Each system of diene or triene has a given fixed value at which maximum absorption is expected to occur according to Woodward rules. This given fixed value is called the base or parent value. If the two double bonds are trans to each other, the diene is said to be transoid. If the two double bonds belong to different rings, the system is said to be heteroanular and the base value in each case is 215nm. If the double bonds are cis to each other (cisoid), or the two double bonds are in the same ring (homoanular), then the base value is 253nm.

Since λmax = base value + ∑ substituent contributions + ∑ other contributions, if the other contributions are not very significant, homoanular diene will have a greater λmax because of its larger base value compared to heteroanular diene. This correlates well with the fact that conjugated systems absorb at a longer wavelength.

You might be interested in

How does the amount of space between particles differ in the ballon and helium cylinder

Ivanshal [37]

In a balloon there is a low pressure within the balloon. This means that the particles are more spaced out. Wheras in the cylinder they are under high pressure, meaning that the particles are much closer together!

8 0

3 years ago

Chemical equations are used to model

Daniel [21]

Answer:

C. chemical reactions

7 0

3 years ago

How many molecules are 4.3 x 10^27 molecules of N2O5<br>

horrorfan [7]

Answer:

<h2>7142.86 moles</h2>

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

$n = \frac{N}{L} \\$

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

$n = \frac{4.3 \times {10}^{27} }{6.02 \times {10}^{23} } \\ = 7142.857...$

We have the final answer as

<h3>7142.86 moles</h3>

Hope this helps you

6 0

3 years ago

Please help asap

Helen [10]

C. carbon
sodium is an
oxygen is o
cl is chlorine

4 0

3 years ago

What is Chromatography?

andrey2020 [161]

Answer:

Chromatography is the separation of a mixture by passing it in solution or suspension or as a vapor. It's mainly used for separation and analytical study of organic and inorganic mixtures.

Hope this helps :)

6 0

3 years ago

Read 2 more answers