Tag: chemistry

Questions Related to chemistry

Which of the following are true solutions?

chemistry element, compound and mixture different types of solutions various mixtures introduction to solutions

  1. ENO salt in water

  2. Tomato soup

  3. Aam panna

  4. Filtered black tea

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Correct Option: A

If air is taken as a binary solution, the solvent is 

chemistry element, compound and mixture different types of solutions various mixtures introduction to solutions

  1. ${N _2}$

  2. ${O _2}$

  3. $C{O _2}$

  4. ${H _2}$

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Correct Option: A

If air is taken as a binary solution, the solvent is:

chemistry is matter pure different types of solutions various mixtures introduction to solutions

  1. N$ _{ 2 }$

  2. O$ _{ 2 }$

  3. CO$ _{ 2 }$

  4. Ar

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Correct Option: A
Explanation:

(A) option is correct.

Explanation:
Air is mainly composed of oxygen and nitrogen gas. Around 78% is nitrogen gas and 21% is oxygen. Since the nitrogen content is more than oxygen so nitrogen will be the solvent and oxygen will be the solute if air is considered as binary solution.

In a glass we are having half filled water. Then we are continuously adding salt to the water and salt is getting dissolved into water. But a state occur when water is not able to dissolve salt. Then the solution is called as 

chemistry is matter pure different types of solutions various mixtures introduction to solutions

  1. Unsaturated solution

  2. Saturated solution

  3. Both A and B

  4. Super saturated solution

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Correct Option: B
Explanation:

A saturated solution is formed due to maximum concentration of a solute dissolved into solvent. The additional solute will not dissolve in a saturated solution.

What volume would you dilute 0.2 L of a 15 M solution to obtain a 3 M solution?

chemistry introduction to analytical chemistry different types of solutions various mixtures introduction to solutions

  1. 1L

  2. 225L

  3. 10L

  4. 0.4L

  5. 0.1L

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Correct Option: A
Explanation:
We know that :

$\displaystyle M _1V _1 = M _2V _2 $ 

Given :

$\displaystyle  M _1 = 15 $  M
$\displaystyle V _1 = 0.2 $ L
$\displaystyle  M _2 =3$  M
$\displaystyle  V _2 =$  ????

$\displaystyle  15 \times 0.2 = 3 V _2$
Thus, $\displaystyle  V _2 = 1$  L

Hence, the correct option is A.

In the upper layers of the earth, that is, in the crust, the most abundant metal is:

chemistry production of metals extraction of aluminium metallurgy of aluminium extraction of metals by electrolysis

  1. zinc

  2. copper

  3. iron

  4. aluminium

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Correct Option: D
Explanation:
Aluminum is the third most abundant element and the most abundant metal in Earth's crust by weight with an abundance of $8.1 \%$

(a) Roasting and calcination are the two processes to reduce the metal oxides to the respective metals.
(b) Magnesium is extracted from its ore by electrolytic reduction process.
(c) Cryolite is used in metallurgy of aluminium in order to increase the fusibility and conductivity
(d) I Hall's process bauxite is leached with the help of ${Na} _{2}{CO} _{3}$.
Which of the following options regarding the above statements is correct?

chemistry production of metals extraction of aluminium metallurgy of aluminium extraction of metals by electrolysis

  1. a, b and c

  2. b, c and d

  3. c and d

  4. only a

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Correct Option: B
Explanation:

(b) Magnesium is extracted from its ore by electrolytic reduction process.
(c) Cryolite is used in metallurgy of aluminium in order to increase the fusibility and conductivity
(d) I Hall's process bauxite is leached with the help of ${Na} _{2}{CO} _{3}$. statements are correct. The concentrated ore is converted into metal oxide by calcination or roasting.

State the function of fluorspar in the metallurgy of aluminium.

chemistry production of metals extraction of aluminium metallurgy of aluminium extraction of metals by electrolysis

  1. to increase conductivity

  2. to decrease conductivity

  3. to increase ductility

  4. none of these

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Correct Option: A
Explanation:

Pure alumina melts at about $2000^oC$ and is a bad conductor of electricity. If fused cryolite and fluorspar is added, the mixture melts at $900^0C$ and solution becomes a good conductor of electricity. 

State the function of cryolite?

chemistry production of metals extraction of aluminium metallurgy of aluminium extraction of metals by electrolysis

  1. to increase conductivity

  2. to decrease conductivity

  3. to increase ductility

  4. none of these

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Correct Option: A
Explanation:

Pure alumina melts at about $2000^oC$ and is a bad conductor of electricity. If fused cryolite and fluorspar is added, the mixture melts at $900^oC$ and solution becomes a good conductor of electricity. 

The electrolyte used in electrolytic refining of impure aluminium is __________.

chemistry production of metals extraction of aluminium metallurgy of aluminium extraction of metals by electrolysis

  1. $AI _2O _{3} + CaF _{2}$

  2. $Na _{3}AlF _{6} + CaF _{2}$

  3. $Al _2O _{3}, Na _{3}AlF _{6} and CaF _{2}$

  4. Any aluminium salt is molten state

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Correct Option: C
Explanation:

In the metallurgy of aluminium, purified $Al _2O _3$ is mixed with $Na _3AlF _6$ or $CaF _2$ which lowers the melting point of the mix and brings conductivity.