Tag: chemistry

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

$CuO+(X) \rightarrow CuSO _4+H _2O$ 

Here, $(X)$ is:

  1. $CuSO _4$
  2. $HCl$
  3. $H _2SO _4$
  4. $HNO _3$
Reveal answer Fill a bubble to check yourself
C Correct answer
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).

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

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

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

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

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

An example is given below.

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

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

Chlorine is evolved by the action of:

  1. ${ H } _{ 2 }{ SO } _{ 4 } \ on\ NaCl$
  2. $HCl\ on\ { K } _{ 2 }{ SO } _{ 4 }$
  3. $HCl \ on\ KMN{ O } _{ 4 }$
  4. $HN{ O } _{ 3 }\ on\ KCl$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

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

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

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

  1. $(NH _{4}) _{2}CO _{3}$
  2. $Na _{2}HPO _{3}$
  3. $NaH _{2}PO _{3}$
  4. $CH _{3}COOK$
Reveal answer Fill a bubble to check yourself
C Correct answer
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. 

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

 Heat gain makes ice to:

  1. freeze

  2. evaporate

  3. melt

  4. dissolve
Reveal answer Fill a bubble to check yourself
C Correct answer
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$.

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

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?

  1. Expansion

  2. Contraction

  3. Both expansion and contraction.

  4. Neither expansion and contraction.
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

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

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.

  1. contracts

  2. expands

  3. evaporates

  4. condenses
Reveal answer Fill a bubble to check yourself
A Correct answer
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.