Tag: group 17 elements - properties

Questions Related to group 17 elements - properties

In KI solution, $ I _2 $ readily dissolves and forms :

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

  1. $ I^{-}$

  2. $ KI _2 $

  3. $ KI _2^- $

  4. $ KI _3 $

Show answer
Correct Option: D
Explanation:

In KI solution, $I _2$ readily dissolves and forms $KI _3$ which contains polyhalide ion $I _3^-$


$KI + I _2  \rightarrow KI _3$

Due to this, iodine is partly soluble in water but highly soluble in the $KI$ solution.

So, the correct option is $D$

Correct order of reactivity of halogens is:

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

  1. $I _2 > Br _2 > Cl _2 > F _2$

  2. $Br _2 > I _2 > Cl _2 > F _2$

  3. $Cl _2 > Br _2 > I _2 > F _2$

  4. $F _2 > Cl _2 > Br _2 > I _2$

Show answer
Correct Option: D
Explanation:

The reactivity of halogens decreases with increase in atomic number of halogens. So the correct order of reactivity of halogens is $F _2 > Cl _2 > Br _2 > I _2.$

Iodide of MilIon's base is :

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

  1. $HIO _3$

  2. $K _2Hgl _4$

  3. $NH _2HgO.HgI $

  4. $Hg(NH _2)I$

Show answer
Correct Option: C
Explanation:

Iodide of MilIon's base is $\displaystyle NH _2HgO.HgI$
It is formed when Nessler's reagent (alkaline solution of $\displaystyle K _2[HgI _4]$) reacts with $NH _3$. 

Iodide of MilIon's base is a reddish brown ppt.

Which two of the following salts are used for preparing iodized salt?
$(i)   KIO _3$
$(ii)  KI$
$(iii)  I _2$
$(iv)  HI$

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

  1. $(i)$ and $(ii)$

  2. $(i)$ and $(iii)$

  3. $(ii)$ and $(iv)$

  4. $(iii)$ and $(iv)$

Show answer
Correct Option: A
Explanation:
Iodised salt is table salt mixed with a small amount of various salts of the element iodine.
$KIO _3$ and $KI$ are used for preparing iodised salt.
Potassium iodate and potassium iodine is used in the iodized salt to prevent the iodine deficiency.

Iodine exists in which form in iodised salt.

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

  1. $I _2$

  2. $NaIO _3$

  3. $ICl$

  4. $IO^- _4$

Show answer
Correct Option: B
Explanation:

Iodised salt is table salt mixed with a minute amount of one of the four iodine containing salts of hydroiodic acid or iodic acid: potassium iodate or potassium iodine and sodium iodate or sodium iodide.

Assertion: Iodine is more soluble in water than in carbon tetrachloride.
Reason: Iodineis a polar compound.

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

  1. If both assertion and reason are true and the reason is a correct explanation of the assertion.

  2. If both assertion and reason are true but reason is not a correct explanation of the assertion.

  3. If the assertion is true but reason is false

  4. If both the assertion and reason are false

  5. If the assertion is false but the reason is true

Show answer
Correct Option: D
Explanation:

Iodine is less soluble in water than in carbon tetrachloride. Iodine is a non polar compound.
Iodine, being a non-polar compound is more soluble in $CCl _4$ (non-polar compound) than in water because "like dissolve like". So both the assertion and reason are false.

Elements of which family are in colored gaseous state, in liquid state and with metallic properties.

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

  1. least-reactive family of elements

  2. alkali metals

  3. halogen family of elements

  4. noble gases

  5. family whose oxides form acids in water

Show answer
Correct Option: C
Explanation:

Elements of halogen family are in colored gaseous state, in liquid state and with metallic properties.
At room temperature, fluorine and chlorine are gases, bromine is a liquid and iodine is a solid.
The colours of fluorine, chlorine, bromine and iodine are yellow, greenish yellow, red and violet.
Iodine has metallic luster.

Halogens have similar reactivity because :

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

  1. they have the same number of protons

  2. they have the same number of electrons

  3. they have similar outer shell electron configurations

  4. they have valence electrons with the same quantum numbers

  5. they have the same number of neutrons

Show answer
Correct Option: C
Explanation:

Halogens have similar reactivity because they have similar outer shell electron configurations of $\displaystyle  ns^2np^5$. 
Thus, all halogens gain one electron to complete octet. Thus, they form uni-negative ion (anion).

When a dry solid is treated with a mild oxidizing agent, a purple solid is produced. What is the dry solid?

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

  1. $N _2$

  2. $KI$

  3. $CCl _4$

  4. $AgNO _3$

  5. $CaCO _3$

Show answer
Correct Option: B
Explanation:

A purple solid (iodine) is produced by treatment of the dry solid $KI$ with a mild oxidizing agent. The mild oxidising agent oxidizes iodide ion to iodine.

Which form negative ions in an ionic bond?

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

  1. Alkali metals

  2. Alkaline Earth metals

  3. Noble gases

  4. Halogens

  5. Transition metals

Show answer
Correct Option: D
Explanation:

Halogens have 7 electrons in their valence shell.

They need 1 electron to complete their octet.
Hence, during the formation of ionic bond they accept an electron and form negative ions.