Tag: chemistry

Questions Related to chemistry

$CuO+(X) \rightarrow CuSO _4+H _2O$ 

Here, $(X)$ is:

chemistry chemistry in everyday life metal oxides and non metal oxides reactions of acids and bases properties of acids and bases

  1. $CuSO _4$

  2. $HCl$

  3. $H _2SO _4$

  4. $HNO _3$

Show answer
Correct Option: C
Explanation:

Acid and base react together, neutralize each other and form salt and water.

$Acid + Base \rightarrow Salt + water$
Here $CuO$ acts as a base and the salt formed is $CuSO _4$, along with formation of water $(H _2O)$.
Since the salt formed is $CuSO _4$, the reacting acid should be sulphate ion ($SO _4^{2-}$) donor, and water would not have been formed if $CuO\  and\  CuSO _4$  would have reacted together. Thus $H _2SO _4$ is the acid that will react with $CuO$ to give $CuSO _4\ and\ H _2O$. The reaction occurs as follows :-
$CuO+H _2SO _4\rightarrow CuSO _4+H _2O$
Hence, the correct answer is option (C).

The equation for the action of a dilute acid on a metal oxide is following:

     Metal oxide + dilute acid $\rightarrow$ Metal salt + Water

chemistry chemistry in everyday life metal oxides and non metal oxides reactions of acids and bases properties of acids and bases

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Given statement is true. Since water is also formed along with salt .

An example is given below.

$CaO+{ 2HNO } _{ 3 }\rightarrow Ca\left( { NO } _{ 3 } \right) _{ 2 }+{ H } _{ 2 }O$

Chlorine is evolved by the action of:

chemistry chemistry in everyday life metal oxides and non metal oxides reactions of acids and bases properties of acids and bases

  1. ${ H } _{ 2 }{ SO } _{ 4 } \ on\ NaCl$

  2. $HCl\ on\ { K } _{ 2 }{ SO } _{ 4 }$

  3. $HCl \ on\ KMN{ O } _{ 4 }$

  4. $HN{ O } _{ 3 }\ on\ KCl$

Show answer
Correct Option: C
Explanation:

Option $(C)$ is the correct answer.
$Chlorine$ is evolved by the action of $\displaystyle HCl$ on $\displaystyle KMnO _4$
$\displaystyle 2KMnO _4+16HCl \rightarrow 2KCl + 2MnCl _2+8H _2O + 5Cl _2$

Identify acidic salt which can react with one mole of base among the following.

chemistry acids, bases and salts metal oxides and non metal oxides reactions of acids and bases properties of acids and bases

  1. $(NH _{4}) _{2}CO _{3}$

  2. $Na _{2}HPO _{3}$

  3. $NaH _{2}PO _{3}$

  4. $CH _{3}COOK$

Show answer
Correct Option: C
Explanation:

$H _3PO _3$ is a dibasic acid. In its structure, one oxygen atom is bonded to $P-$ atom via a double bond. $2$ $O-$atoms are bonded to $H-$atoms causing acidity. The third $H$ is directly attached to $P-$ atom responsible for its reducing behavior. 

In $NaH _2PO _3$, one acidic $H$ is replaced by $Na$. Only one $H$ is left which causes the acidic behavior in the salt and hence, will react with one mole of base. 

 Heat gain makes ice to:

chemistry changes around us can all changes be reversed? substances and objects classification of changes

  1. freeze

  2. evaporate

  3. melt

  4. dissolve

Show answer
Correct Option: C
Explanation:

When heat flows through the ice, the ice will melt. 

The liquid has more energy than the solid, mainly because the molecular bonds in the solid adjust to low-energy positions. So energy, when flowed in, will convert the solid to the liquid.
Freezing will happen if the there is heat loss to ice.
Evaporation will happen if the heat gain is very high that makes the ice to convert to water vapor.
The correct answer is option $ C$.

Which of the following is/are different ways to bring a change?

chemistry changes around us can all changes be reversed? substances and objects classification of changes

  1. Expansion

  2. Contraction

  3. Evaporation

  4. All of the above.

Show answer
Correct Option: D
Explanation:

All of the following is/are different ways to bring a change.
Expansion, Contraction, Evaporation,Melting.

What are the different conditions for a chemical reaction to take place?

chemistry changes around us can all changes be reversed? substances and objects classification of changes

  1. Heating

  2. Mixing

  3. Boiling

  4. All of the above

Show answer
Correct Option: D
Explanation:

D, Temperature and close contact plays important roles in chemical reactions. These factors affects the activation energy of the reaction.

In the tools which are used to dig the soil, the iron blade in these tools fixed to the wooden handle. Which of the following is used during the change?

chemistry changes around us can all changes be reversed? substances and objects classification of changes

  1. Expansion

  2. Contraction

  3. Both expansion and contraction.

  4. Neither expansion and contraction.

Show answer
Correct Option: C
Explanation:

Both expansion and contraction is used during the change.
The iron blade has a ring in which the wooden handle is fixed. The ring is slightly smaller in size than the wooden handle.The ring is heated and it becomes slightly larger in size (expands). The handle  fits into the ring. When the ring cools it contracts and tightly fits on the handle.

The iron blade has a ring in which the wooden handle is fixed. The ring is slightly smaller in size than the wooden handle.
The ring is heated . When the ring cools it _____ and tightly fits on the handle.

chemistry changes around us can all changes be reversed? substances and objects classification of changes

  1. contracts

  2. expands

  3. evaporates

  4. condenses

Show answer
Correct Option: A
Explanation:

The iron blade has a ring in which the wooden handle is fixed. The ring is slightly smaller in size than the wooden handle.
The ring is heated and it becomes slightly larger in size (expands). The handle  fits into the ring. When the ring cools it contracts and tightly fits on the handle.

Zinc metal burns in air only on strong heating to form :

chemistry metals reaction of metals reactions of metals chemical properties of metals

  1. zinc chloride

  2. zinc sulphide

  3. zinc oxide

  4. zinc hydroxide

Show answer
Correct Option: C
Explanation:

Zinc metal burns in air only on strong heating to form zinc oxide.

$Zinc + Oxygen \xrightarrow{\Delta} Zinc\,oxide$

$2Zn + O _2 \xrightarrow{\Delta} 2ZnO$