Tag: chemistry

Questions Related to chemistry

________ exist as diatomic molecules at room temperature.

chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

  1. Alkali metals

  2. Alkaline earth metals

  3. Noble gases

  4. Halogens

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Correct Option: D
Explanation:

Each halogen has 7 electrons in its outer shell. Atoms are much more stable when they have 8 electrons in their outer shell. The two halogen atoms form a covalent bond with each other to form diatomic molecules in order to complete their octet.

Which of the following is not a green house gas?

chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

  1. $CO _2$

  2. $CH _4$

  3. $O _3$

  4. $N _2X$

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Correct Option: D
Explanation:

Greenhouse gases are gases in an atmosphere that absorbs and releases radiation This process is the cause of the greenhouse effect. The main greenhouse gases in Earth's atmosphere are water vapour, carbon dioxide, methane, nitrous oxide, and ozone. So $N _2X$ is not greenhouse gas.

Hence option $D$ is correct.

Which of the following does not truly represent the property indicated against it?

chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

  1. $ Br _2 < Cl _2 < F _2 $ : Oxidising power

  2. $ Br < Cl < F $ : Electronegativity

  3. $ Br < F < Cl $ : Electron affinity

  4. $ Br _2 < Cl _2 < F _2 $ : Bond energy

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Correct Option: D
Explanation:
The correct arrangements along with properties are written against them.

$ Br _2 < Cl _2 < F _2 $ : Oxidising power

$ Br < Cl < F $ : Electronegativity

$ Br < F < Cl $ : Electron affinity

$ F _2 < Br _2 < Cl _2 $ : Bond energy

Thus,we see that the order of bond energy is incorrect in the question. The correct order is given above. 

Hence, option D is correct.
In the gas phase, the colours of the halogens very remarkably :
Fluorine - Pale yellow
Chlorine - Pale greenish-yellow
Bromine - Deep red-brown
Iodine - Deep violet

As one moves from $F _2$ to $I _2$, the difference between the two energy levels:

chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

  1. decreases and probability of transition increases

  2. increases and probability of transition increases

  3. remains unchanged and probability of transition remains unchanged

  4. depends on the temperature

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Correct Option: A
Explanation:

As we move down the group, repulsion decreases.Because of the difference between the two energy levels decreases and probability of transition increases and colour become more dense.

The only non-metal, which is a liquid at room temperature is:

chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

  1. $ \mathrm{O} _{2} $

  2. $\mathrm{F} _{2}$

  3. $ \mathrm{N} _{2}$

  4. $\mathrm{B}\mathrm{r} _{2}$

Show answer
Correct Option: D
Explanation:

$Br _2$ is the only non-metal which is liquid at room temperature

Which of the following is the only nonmetal that appears as a liquid in its elemental form under standard conditions?

chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

  1. $Cl$

  2. $F$

  3. $Br$

  4. $I$

Show answer
Correct Option: C
Explanation:

Option $C$ is the correct answer.

Bromine or $Br$ is the only non-metal which is a liquid in its elemental form under standard conditions.
Fluorine and chlorine are gases. Whereas, iodine is solid under standard conditions.

Least melting point is shown by the compound-

chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

  1. $PbCl _2$

  2. $SnCl _4$

  3. $NaCl$

  4. $AlCl _3$

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Correct Option: B
Explanation:

We know that greater the molecular size is; greater will be van der Waal force of attraction between then and higher will be its melting point.

Among given species since in $AlCl _3$; Al has the least size so the van der Waal force of attraction will be least and the melting point of it is lowest. But because of a molecular crystalline structure of $SnCl _4$, it has least melting point among given species.

Select the correct order of polymerization tendency from the following :

chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

  1. $Si\, -\, O\, >\, P\, -\, O\, >\, S\, -\, O\, >\, Cl\, -\, O$

  2. $P\, -\, O\, >\, S\, -\, O\, >\, Cl\, -\, O\, >\, Si\, -\, O$

  3. $Cl\, -\, O\, >\, S\, -\, O\, >\, P\, -\, O\, >\, Si\, -\, O$

  4. $Si\, -\, O\, <\, P\, -\, O\, <\, S\, -\, O\, <\, Cl\, -\, O$

Show answer
Correct Option: A
Explanation:

Th tendency to form pi bond increases in the order
$SiO<PO<SO<ClO$
Since the size of Cl tom is smaller compared to Si, P and S, in case of Cl, less internuclear distance results in more effective sideways overlapping.
With increase in the tendency to form  the pi bond, the tendency for polymerization decreases.
Hence, the decreasing order for the tendency for polymerization is $SiO>PO>SO>ClO$.

Consider occurance of the halogen family in the periodic table and choose true statements.
Statement I. Fluorine is the most active nonmetallic element in the periodic table.
Statement II. As you move down the family the state of the halogens is from a solid to a gaseous state.
Statement III. By filling the outermost d orbital, the halogen elements can be converted to ions.

chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

  1. I and III

  2. II only

  3. I and II

  4. I only

  5. II and III

Show answer
Correct Option: D
Explanation:

Only statement I is the true statement. 
Statement I. Fluorine is the most active nonmetallic element in the periodic table.
Statement II. As you move down the family the state of the halogens is from a gas to a solid state.
Thus, fluorine and chlorine are gases, bromine is a liquid and iodine is a solid.
Statement III. By filling the outermost p orbital the halogen elements can be converted to ions.

Treatment of the dry solid _____ with a mild oxidizing agent produces a purple solid.

chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

  1. $N _{2}$

  2. $KI$

  3. $CCl _{4}$

  4. $AgNO _{3}$

Show answer
Correct Option: B
Explanation:

An oxidising agent would displace iodine from potassium iodide. When iodine gets removed, free iodine appears purple in colour.