Tag: chemistry

Questions Related to chemistry

Write the ionic equation for reaction between manganese dioxide and hydrochloric acid.

distinguish between black copper oxide and black manganese dioxide practical work chemistry

  1. $MnO _2(s)+ 2Cl^{-}(aq) \rightarrow Mn^{2+}(aq) + Cl _2(g) + 2H _2O(l)$

  2. $MnO _2{(s)} + 4H^{+}{(aq)} + 2Cl^{-}{(aq)} \rightarrow Mn^{2+}{(aq)} + Cl _2{(g)} + 2H _2O{(l)}$

  3. $MnO _2{(s)} + 3H^{+}{(aq)} + 2Cl^{-}{(aq)} \rightarrow Mn^{2+}{(aq)} + Cl _2{(g)} + 2H _2O{(l)}$

  4. $MnO _2{(s)} + 4H^{+}{(aq)} + 2Cl^{-}{(aq)} \rightarrow Mn^{2+}{(aq)} + Cl{(g)} + 2H _2O({l})$

Show answer
Correct Option: B
Explanation:

$MnO _2{(s)} + 4H^{+}{(aq)} + 2Cl^{-}{(aq)} \rightarrow Mn^{2+}{(aq)} + Cl _2{(g)} + 2H _2O{(l)}$

The salt formed on reaction of copper oxide with hydrochloric acid is :

distinguish between black copper oxide and black manganese dioxide practical work chemistry

  1. Cuprous chloride

  2. Cupric chloride

  3. Both formed in $1:2$ ratio

  4. Both formed in $1:3$ ratio

Show answer
Correct Option: B
Explanation:

copper oxide $+$ hydrochloric acid $\rightarrow $ copper chloride $+$ water

 $CuO+2HCl \rightarrow  CuCl _{2}+H _{2}O$

The element having very high ionization enthalpy but zero electron gain enthalpy is: 

chemistry the periodic table periodic trends in chemical properties alkali metals study of specific groups

  1. H

  2. F

  3. He

  4. Be

Show answer
Correct Option: C
Explanation:

Inert gases have very high ionization enthalpy and zero electron gain enthalpy. So the correct answer is He.

Which of the following exists as an individual gas-phase atom under standard conditions?

chemistry the periodic table periodic trends in chemical properties alkali metals study of specific groups

  1. $\displaystyle C$

  2. $\displaystyle N$

  3. $\displaystyle O$

  4. $\displaystyle F$

  5. $\displaystyle Ne$

Show answer
Correct Option: E
Explanation:

Option E is the correct answer.

${Ne} $ or Neon is an inert gas. It has a complete octet (2,8) with 8 electrons in its outermost orbit and is highly stable. And thus under standard conditions it remains as an individual gas phase atom without forming a molecule. 

Group contains the noble gases is_______ group.

chemistry the periodic table periodic trends in chemical properties alkali metals study of specific groups

  1. 16th

  2. 17th

  3. 18th

  4. Both B and C

Show answer
Correct Option: C
Explanation:

Group 18 contains noble gases.


They have already stable and octet configuration that is they contain 8 electrons in their outer most shell.

Hence they have high ionization potential and zero electron affinity.

They do not participate in chemical bonding because already they are stable.

Option C is correct.

Inert gases are otherwise called zero valent elements.
State whether the given statement is true or false.

chemistry the periodic table periodic trends in chemical properties alkali metals study of specific groups

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Given statement is true.
In general noble elements have a stable configuration that is octet configuration with all orbitals filled. Hence no tendency in either accepting or donating electrons. This is why those are called zero valent elements. 

The inert gas present in the second long period is Xe.

chemistry the periodic table periodic trends in chemical properties alkali metals study of specific groups

  1. True

  2. False

  3. Either

  4. Neither

Show answer
Correct Option: A
Explanation:

Xe is present in 5th period of periodic table.


The period 4 and 5 are called long periods.
 
So, the Xe is present in second long period.

The atomic number not found under the zero group elements is: 

chemistry the periodic table periodic trends in chemical properties alkali metals study of specific groups

  1. 16

  2. 18

  3. 36

  4. 54

Show answer
Correct Option: A

Why noble gases are generally non-reactive?

chemistry the periodic table periodic trends in chemical properties alkali metals study of specific groups

  1. Because they are classified as zero group elements

  2. Because they are in gaseous state

  3. Due to their stable electronic configuration

  4. Because they are p-block elements

Show answer
Correct Option: C

The electronic configuration of Argon is:

chemistry the periodic table periodic trends in chemical properties alkali metals study of specific groups

  1. $1s^2, 2s^22p^6, 3s^23p^6$

  2. $1s^2, 2s^22p^6, 3s^23p^2$

  3. $1s^2, 2s^22p^6, 3s^23p^4$

  4. $1s^2, 2s^22p^6, 3s^23p^63d^{10}, 4s^24p^6$

Show answer
Correct Option: A