Tag: group 17 elements - properties

Questions Related to group 17 elements - properties

Iodine gas turns strach iodide paper :

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

  1. Blue

  2. Red

  3. Colourless

  4. Yellow

Show answer
Correct Option: A
Explanation:

Iodine reacts with starch to produce a blue/black color.

The order of basicity of halides is :

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

  1. $Cl < Br < I < F$

  2. $F < I < Br < Cl$

  3. $I < Br < Cl < F$

  4. $Cl < F < I < Br$

Show answer
Correct Option: C
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 $F>Cl>Br>I$

 Essential trace element involved in physiology of thyroid glands :

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

  1. K

  2. Mg

  3. Ni

  4. $I _{2}$

Show answer
Correct Option: D
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.

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

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

  1.  $NaI$

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

  3. A and B

  4. non of these

Show answer
Correct Option: A
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 $\displaystyle  (NaOI)$

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.

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

  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.

Show answer
Correct Option: D
Explanation:

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

Rest two statements are true.

Tincture of iodine contains _____?

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

  1. $ \displaystyle I _{2}$

  2.  $KI$

  3.  Rectified spirit.

  4. All of these

Show answer
Correct Option: D
Explanation:

Tincture of iodine contains 0.5 ounce iodine,  0.25 ounce KI and 1 pint of rectified spirit.

Iodine deficiency in diet is ____.

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

  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.

Show answer
Correct Option: A,B,C,D
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.

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 :

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

  1. a, b, c

  2. b, c

  3. b, d

  4. all are correct

Show answer
Correct Option: C
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

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

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

  1. chlorine

  2. bromine

  3. soluble chloride

  4. soluble bromine

Show answer
Correct Option: A,B
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.

Which of the following is incorrect?

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

  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

Show answer
Correct Option: B,C,D
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.