Tag: group 17 elements - properties

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Multiple choice group 17 elements - trends in chemical properties group 17 elements - properties p- block elements-ii p-block elements chemistry

The order of basicity of halides is :

  1. $Cl < Br < I < F$
  2. $F < I < Br < Cl$
  3. $I < Br < Cl < F$
  4. $Cl < F < I < Br$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Base is an electron pair donor. The more available the electrons, the more readily they can be donated to form a new bond to the proton and, and therefore the stronger base. When comparing atoms within the same group of the periodic table, the larger the atom the weaker the H-X bond and the lower the electron density making it a weaker base.

Therefore the order of basicity is $F>Cl>Br>I$

Multiple choice group 17 elements - trends in chemical properties group 17 elements - properties p- block elements-ii p-block elements chemistry

 Essential trace element involved in physiology of thyroid glands :

  1. K

  2. Mg

  3. Ni
  4. $I _{2}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Iodine's main role in animal biology is as constituents of the thyroid hormones, thyroxine (T4) and triiodothyronine (T3). These are made from addition condensation products of the amino acid tyrosine, and are stored prior to release in an iodine-containing protein called thyroglobulin. T4 and T3 contain four and three atoms of iodine per molecule, respectively. The thyroid gland actively absorbs iodine from the blood to make and release these hormones into the blood, actions which are regulated by a second hormone TSH from the pituitary. Thyroid hormones are phylogenetically very old molecules which are synthesized by most multicellular organisms, and which even have some effect on unicellular organisms.

Multiple choice group 17 elements - trends in chemical properties group 17 elements - properties p- block elements-ii p-block elements chemistry

Iodine reacts with hot NaOH solution giving the products as-___?

  1. $NaI$
  2. $ \displaystyle NaIO _{3}$.

  3. A and B

  4. non of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Iodine reacts with hot concentrated NaOH solution giving the products sodium iodide (NaI) and  sodium iodate $\displaystyle  (NaIO _3)$.
With cold and dil NaOH, iodine gives sodium hypo iodite $\displaystyle  (NaOI)$
Multiple choice group 17 elements - trends in chemical properties group 17 elements - properties p- block elements-ii p-block elements chemistry

Observe the following statements.
I .Bleaching powder is used in the preparation of chloroform.
II. Bleaching powder decomposes in the presence of $\mathrm{C}\mathrm{o}\mathrm{C}1 _{2}$ to liberate $\mathrm{O} _{2}$.
III. Aqueous $\mathrm{K}\mathrm{H}\mathrm{F} _{2}$ is used in the preparation of fluorine.

  1. I,II and III are correct

  2. Only II is correct.

  3. Only I and III are correct

  4. Only I and II are correct.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Molten $KHF _{2}$ is used in the preparation of fluorine.

Rest two statements are true.

Multiple choice group 17 elements - trends in chemical properties group 17 elements - properties p- block elements-ii p-block elements chemistry

Iodine deficiency in diet is ____.


  1. Solutions of iodine in KI are used in treatment of Goiter.


  2. Goiter is enlargement of thyroid gland.


  3. Iodine deficiency in diet is known to cause Goiter.

  4. Iodine is necessary for normal functioning of the thyroid gland.
Reveal answer Fill a bubble to check yourself
A,B,C,D Correct answer
Explanation
Iodine is necessary for normal functioning of the thyroid gland.
Iodine deficiency in diet is known to cause Goiter.
Goiter is enlargement of thyroid gland.
Solutions of iodine in KI are used in treatment of Goiter.
Multiple choice group 17 elements - trends in chemical properties group 17 elements - properties p- block elements-ii p-block elements chemistry

Which of the following will displace the halogen from the solution of of halide
a $) Br _{2}$ added to an $NaCl$ solution
$\mathrm{b}) Cl _{2}$ added to a $KBr$ solution
$\mathrm{c}) Cl _{2}$ added to an $NaF$ solution
$\mathrm{d}) Br _{2}$ added to to a $KI$ solution
Find the correct answer :

  1. a, b, c

  2. b, c

  3. b, d

  4. all are correct
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$Br^{-}$ can reduce $Cl _{2}$ to $Cl^{-}$ $(E _{cell}=+ve)$

$I^{-}$ can reduce $Br _{2}$ to $Br^{-}$ $(E _{cell}=+ve)$

$E _{cell}=+ve$ in both case

$\therefore$ Reaction is feasible

Multiple choice group 17 elements - trends in chemical properties group 17 elements - properties p- block elements-ii p-block elements chemistry

Iodine can be obtained from NaI solution by the action of:

  1. chlorine

  2. bromine

  3. soluble chloride

  4. soluble bromine
Reveal answer Fill a bubble to check yourself
A,B Correct answer
Explanation

The iodine can be obtained by reacting chlorine or bromine by NaI. This is because the electronegativity of chlorine and bromine is more than the iodine and also the reactivity of chlorine and bromine is more than the iodine.

Multiple choice group 17 elements - trends in chemical properties group 17 elements - properties p- block elements-ii p-block elements chemistry

Which of the following is incorrect?

  1. iodine is a solid

  2. chlorine is insoluble in water

  3. iodine is more reactive than bromine

  4. bromine is more reactive than chlorine
Reveal answer Fill a bubble to check yourself
B,C,D Correct answer
Explanation

Reactivity order:-
$F _2>Cl _2> Br _2>I _2$
Thus, chlorine is more reactive than bromine and bromine is more reactive than iodine.

Chlorine is soluble in water.