Tag: chemistry

Questions Related to chemistry

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

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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.

________ 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

Show answer
Correct Option: D
Explanation:
As halogen are most electronegative and have a high tendency to gain electrons they form negative ions in an ionic bond.
Hence option $D$ is correct.

Statement $1$: Element $Z$ with an electronic configuration of $1s^{2} 2s^{2} 2p^{5}$ can be expected to form the compound $MgZ _{2}$.
Statement $2$: Each atom of $Z$ needs two electrons to fill its valence shell.

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

  1. Both Statement $1$ and Statement $2$ are correct and Statement 2 is the correct explanation of Statement $1$

  2. Both Statement $1$ and Statement $2$ are correct, but Statement $2$ is NOT the correct explanation of Statement $1$

  3. Statement $1$ is correct, but Statement $2$ is not correct

  4. Statement $1$ is not correct, but Statement $2$ is correct

Show answer
Correct Option: C
Explanation:

Element Z has electronic configuration ${1s}^2 2s^2 2p^{5}$ , its belongs to 17th group so, it can form compound $MgZ _2$.

Its valency will be one.
It requires 9 elctron to fill its valence shell or it has already 9 electrons. So, statement 2 is wrong.
 

Treatment of the dry solid with a mild oxidizing agent produces a purple solid having formula _______.

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. $AgNO _3$

Show answer
Correct Option: B
Explanation:

Iodine can be displaced from potassium iodide if a more reactive element is made to react with potassium iodide. In the presence of a mild oxidising agent, the iodine ions are oxidised to $I _2$. Iodine is purple in colour.

Identify the gas that would form when hydrobromic acid is combined with nickel (II) sulfide.

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

  1. $NiBr _{2}$

  2. $H _{2}S$

  3. $HBr$

  4. $NiS$

Show answer
Correct Option: B
Explanation:

The gas that would form when hydrobromic acid is combined with nickel (II) sulfide is $H _2S$

$2 HBr(aq) + NiS(s)\rightarrow H _2S + NiBr _2$.
Hence option B is correct.

When $KClO _3$ is heated in presence $MnO _2$ the product is:

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

  1. $O _2$

  2. $Cl _2$

  3. $O _3$

  4. none of these

Show answer
Correct Option: A
Explanation:

When $KClO _3$ is reacted with $MnO _2$ in presence of heat it forms $KCl,O _2,MnO _2$ respectively.

$KClO _3+MnO _2\longrightarrow KCl+O _2+MnO _2$

Hence option A is correct.

Which of the following is most acidic?

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

  1. $HClO$

  2. $HClO _2$

  3. $HClO _3$

  4. $HClO _4$

Show answer
Correct Option: D
Explanation:

As the oxidation number of chlorine(non metal) increases in the given acids the acidic nature of the compound increases. So the oxidation numbers of chlorine in the given compounds are $+1,+3,5,+7$ respectively.

So the acidic nature of $HClO _4$ is high.
Hence option D is correct.