Tag: chemical reactions

Questions Related to chemical reactions

Which of the following can be classified as a strong electrolyte?

chemistry electrolysis electrolytes and non-electrolytes introduction to electrolysis chemical reactions

  1. $\displaystyle { Br } _{ 2 }$

  2. $\displaystyle { C } _{ 6 }{ H } _{ 12 }{ O } _{ 6 }$

  3. $\displaystyle Ca{ Cl } _{ 2 }$

  4. $\displaystyle { H } _{ 2 }O$

  5. $\displaystyle N{ O } _{ 3 }$

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Correct Option: C
Explanation:

Option C is the correct answer.

$CaCl _2$ in aqueous solution dissociates to give one $Ca^{2+}$ and two $Cl^-$ ions.
Any substance which dissociates to form ions can be termed as an electrolyte.
Here Calcium Chloride gives one ion of Calcium and two Chloride ions. That is, from $CaCl _2$ a total of three ions are formed. Hence it can be classified as a strong electrolyte. The strong electrolytes dissociate completely in the solution. Here only $CaCl _2$ is the only compound which completely dissociates.

What is an electrolyte?

chemistry electrolysis electrolytes and non-electrolytes introduction to electrolysis chemical reactions

  1. Electrolytes are substances that dissolve by separating into ions in solution.

  2. Electrolytes are substances that do not conduct electricity but dissolve in water.

  3. Electrolytes are substances that have covalent bonds.

  4. Electrolytes are substances that share electrons.

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Correct Option: A
Explanation:

Electrolyte is an substance that dissolve by separating into ions in solution . They even can conduct electricity. As their ions are free to carry current.

Two solutions of X and Y electrolytes are taken in two beakers and diluted by adding $500$ mL of water. $\Lambda _m$ of X increases by $1.5$ times while that of Y increases by $20$ times, what could be the electrolytes X and Y?

chemistry electrolysis electrolytes and non-electrolytes introduction to electrolysis chemical reactions

  1. $X\rightarrow NaCl, Y\rightarrow KCl$

  2. $X\rightarrow NaCl, Y\rightarrow CH _3COOH$

  3. $X\rightarrow KOH, Y\rightarrow NaOH$

  4. $X\rightarrow CH _3COOH, Y\rightarrow NaCl$

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Correct Option: B
Explanation:

On dilution, the molar conductivity of X increases by 1.5 times and Y by 20 times. Hence, X is a strong electrolyte and Y is a weak electrolyte.


Hence, option B is correct.

The substances whose aqueous solutions conduct electricity are called : 

chemistry electrolysis electrolytes and non-electrolytes introduction to electrolysis chemical reactions

  1. electrolytes

  2. non-electrolytes

  3. conductors

  4. metals

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Correct Option: A
Explanation:

The substances whose aqueous solutions conduct electricity are called electrolytes.

Which of the following is an insulator?

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. Wood

  2. Iron

  3. Graphite

  4. Silver

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Correct Option: A
Explanation:

Insulators donot conduct electricity due to the absence of ions or electrons.

Iron is metal therefore has pool of electrons on the surface and is a conductor.
Graphite has extensive $\pi$ electron cloud and is thus a conductor.
Silver is a metal and is a very good conductor of electricity.
Wood is made of organic molecule, thus its an insulator.
Option A is correct

Insulators:

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. conduct electricity.

  2. do not conduct electricity.

  3. conduct electricity only at low temperatures.

  4. conduct electricity at room temperature.

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Correct Option: B

What is [CN-] in a solution prepared by mixing 100ml 0.1M $KCN$ and 100ml 0.1M $HCl$. (Ka of $HCN$ is 510^-6 M)?

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. $5\times10^{-4} M$

  2. $2\times10^{-6} M$

  3. $2\times10^{-5} M$

  4. $4 \times10^{-6} M$

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Correct Option: C

A compass placed in an electric field will be deflected due to:

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. heating effect of current

  2. magnetic effect of current

  3. conducting effect

  4. resistance of the needle to the electric field

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Correct Option: B
Explanation:

An electric current causes a magnetic field around it just like a magnet causes a magnetic field. When you moved the compass near an electric field, the magnetic field produced due to the electric field deflects the compass.


Hence, the correct option is $\text{B}$

Which of the following is a good conductor of electricity?

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. Tap water

  2. Distilled water

  3. Sea water

  4. Rain water

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Correct Option: A,C,D
Explanation:
Sea water, tap water, and rainwater comprise of salt and many other impurities whereas distilled is void of such impurities. 

Those impurities, act as ions and help in the transfer of charge.
 
Hence, they are good conductor of electricity.

Distilled water is highly purified water that does not contain any salts. Hence, it do not conduct electricity.

Therefore, option A, C and D are correct.

Which of the following does not conduct electricity ?

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. Molten NaoH

  2. Molten KOH

  3. Solid NaCI

  4. Aqueous NaCI

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Correct Option: C