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Questions
Why are halogens coloured?
Why are all halogens coloured?
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Solution
Almost all halogens are coloured. This is because halogens absorb radiation in the visible region. This results in the excitation of valence electrons to a higher energy region. Since the amount of energy required for excitation differs for each halogen, each halogen displays a different colour.
RELATED QUESTIONS
Fluorine is a stronger oxidising agent than chlorine. Why?
Account for the following :
Acidic character increases from HF to HI.
F2 has lower bond dissociation enthalpy than Cl2. Why?
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Which halogen compound in each of the following pairs will react faster in SN2 reaction
(CH3)3 C – Cl or CH3 – Cl
Write two uses of ClO2.
Arrange the following in the order of property indicated for the given set:
HF, HCl, HBr, HI - increasing acid strength.
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Select the correct alternative from the choices given :
The correct order of increasing acidic strength of the oxoacids of chlorine is:
Which one has the lowest boiling point?
Which is the strongest acid in the following:
Bond dissociation enthalpy of E–H (E = element) bonds is given below. Which of the compounds will act as the strongest reducing agent?
| Compound | \[\ce{NH3}\] | \[\ce{PH3}\] | \[\ce{AsH3}\] | \[\ce{SbH3}\] |
| Δdiss (E – H)/kJ mol–1 | 389 | 322 | 297 | 255 |
Reduction potentials of some ions are given below. Arrange them in decreasing order of oxidising power.
| Ion | \[\ce{CIO^{-}_{4}}\] | \[\ce{IO^{-}_{4}}\] | \[\ce{BrO^{-}_{4}}\] |
| Reduction potential EΘ/V |
EΘ = 1.19 V | EΘ = 1.65V | EΘ = 1.74 V |
Which of the following is isoelectronic pair?
The reaction \[\ce{3ClO- (aq) -> ClO3- (aq) + 2Cl- (aq) + 2Cl- (aq)}\] is an example of
Statement I: Acid strength increases in the order given as HF << HCl << HBr << HI.
Statement II: As the size of the elements F, Cl, Br, and I increase down the group, the bond strength of HF, HCl, HBr, and HI decreases and so the acid strength increases.
In the light of the above statements, choose the correct answer from the options given below.
