Tag: group 17 elements - properties

Questions Related to group 17 elements - properties

Which of the following co exist-

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

  1. $HI^{-} _{2}$

  2. $HBr _{2}^{-}$

  3. $HF _{2}^{-}$

  4. $HCl _{2}^{-}$

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Correct Option: A

The most covalent halide is:

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

  1. $Al{F} _{3}$

  2. $Al{Cl} _{3}$

  3. $Al{Br} _{3}$

  4. $Al{I} _{3}$

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Correct Option: D
Explanation:

According to Fajans rule larger the size of anion,more covalent will be the bond . So, according to this most covalent halide is iodide as because it is the least electronegative among all the halides,greater size of halide anion,so in a covalent compound it has the least polarising

The volatility of the Group $17$ elements, chlorine, bromine and iodine, decreases down the group. What is responsible for this?

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

  1. Bond length in the halogen molecule

  2. Bond strength in the halogen molecule

  3. Electronegativity of the halogen

  4. Number of electrons in the halogen molecule

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Correct Option: D
Explanation:

$\text{The volatility of the Group 17 elements decrease down the group due to the increse the numnber of electrons.}$

State whether the given statement is true or false:

In Japan Sunami, there has been increase in radioactive iodine content in salt.
group 17 elements - trends in chemical properties group 17 elements - properties p- block elements-ii p-block elements chemistry

  1. True

  2. False

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Correct Option: A
Explanation:

The given statement is True. 
In Japan Sunami, there has been increase in radioactive iodine content in salt.
Traces of iodine are found in mineral deposits. Iodine also finds its way into the animal system as thyroxin in thyroid glands.

In very recent Sunami in Japan, food materials were banned as they were contaminated with radioactivity . Which of the following was found to have radioactive beyond prescribed limit ?

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

  1. F

  2. Cl

  3. I

  4. At

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Correct Option: C
Explanation:

Tokyo, the city first reported a spike of radioactive iodine in its water supply on March 23, 2011 at levels below the limit for adults but above the threshold of safety for infants; since then, iodine levels in Tokyo's water have declined below both thresholds. 


Above-limit levels of radioactive iodine and cesium have also been found in milk and vegetables in seven prefectures in Japan. 

Hence,option C is correct.


$O _2^+PtF _6^-$ is an orange-coloured compound.

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

  1. True

  2. False

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Correct Option: A
Explanation:

Dioxygenyl hexafluoroplatinate $(O _2^+[PtF _6]^-)$ is a orange coloured salt. It is a solid and is used to prepare co-ordination complexes.

The odd one is:

[note: valency is not a criterion]

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

  1. iodine

  2. sulphur

  3. phosphorus

  4. carbon

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Correct Option: A
Explanation:

Catenation,  chemical linkage into chains of atoms of the same element, occurring only among the atoms of an element that has a valence of at least two and that forms relatively strong bonds with itself. The property is predominant among carbon atoms, significant among sulfur and silicon atoms, and slightly present among germanium, nitrogen, selenium, and tellurium atoms.
here, apart from iodine all other have this property.

Which halogen can be purified by sublimation?

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

  1. $F _2$

  2. $Cl _2$

  3. $Br _2$

  4. $I _2$

Show answer
Correct Option: D
Explanation:

Sublimation is the transition of a substance directly from the solid to the gas phase without passing through the intermediate liquid phase..
At room temperature, fluorine and chlorine are gases, bromine is liquid, and iodine is solid. They form diatomic molecules in the pure state. Since, $I _2$ is solid at room temperature. It will be sublimated and remaining can not be sublimated
Hence, options D is correct.

The decreasing order of bond dissociation energy among halogens is:

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

  1. $\mathrm{F}-\mathrm{F} >\mathrm{C}\mathrm{l}$ -$\mathrm{C}\mathrm{l}> \mathrm{B}$r - $\mathrm{B}$r $>I-I$

  2. $\mathrm{C}\mathrm{l}$ -$\mathrm{C}\mathrm{l}> \mathrm{B}$r - $\mathrm{B}$r $>\mathrm{F}-\mathrm{F}>I-I$

  3. $\mathrm{C}\mathrm{l}$ -$\mathrm{C}\mathrm{l}> \mathrm{B}$r - $\mathrm{B}$r $>I-I>\mathrm{F}-\mathrm{F}$

  4. $I-I>\mathrm{F}-\mathrm{F}>\mathrm{C}\mathrm{l}$ -$\mathrm{C}\mathrm{l}> \mathrm{B}$r - $\mathrm{B}$r

Show answer
Correct Option: B
Explanation:

Bond dissociation energy decrease
down the group
But bonds dissociation energy of 
$F _2$ is less than excepted due to 
large repulsion of $e^-$ in $F _2$


Which of the statements is/are true about the reactivity order is $F _2\, >\, Cl _2\, >\, Br _2\, >\, I _2.$
I. Lower the activation energy for the chain initiation step, more reactive is the halogen.
II. Lower the activation energy for the first chain propagation step, more reactive is the halogen.
III. More negative is the overall heat of the reaction $(\Delta H _{\zeta}^{})$ of halogenation of alkane, more reactive is the halogen.
IV. Lower the activation energy for the second chain-propagation step, more reactive is the halogen.

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

  1. (I), (II)

  2. (I), (II), (III)

  3. (II), (III)

  4. (II), (III), (IV)

Show answer
Correct Option: C
Explanation:

There are two factors that determine the reactivity of the halogenation of alkanes.
1. Lesser the positive value of $E _{act}$ of the first chain propagating step, more reactive is the halogen.
2. Higher the negative value of overall heat of reaction $(\Delta H _{\zeta}^{})$ more reactive is the halogen. This explains high reactivity and explosive violence with which $F _2$ reacts with $CH _4$.