Tag: chemistry

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Multiple choice chemistry nature of matter heterogenous mixture - colloidal solution and its properties suspensions and colloids mixtures

Colloidal solutions of metals like gold can be prepared when their salt solutions react with certain substances like $SnCl _{2}$, formaldehyde, phenyl hydrazine, etc.
2$AuCl _{3}$ + 3$SnCl _{2}$ $\rightarrow$ 3$SnCl _{4}$ + $2Au _{sol}$
The above method is an example of:

  1. reduction method

  2. oxidation method

  3. hydrolysis method

  4. double decomposition method
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

  • A colloid is a heterogeneous system in which one substance is dispersed (dispersed phase) as very fine particles in another substance called dispersion medium.
  • Colloidal solutions of metals like gold can be prepared when their salt solutions react with certain substances like $SnCl _2$, formaldehyde, phenylhydrazine.
In the given reaction,
$2AuCl _3 + 3SnCl _2 \rightarrow 3SnCl _4 + 2Au _{sol}$
The oxidation state of $Sn$ is changing from -2 to -4. So,it is gaining electrons and hence the method is the reduction method.

Multiple choice chemistry nature of matter heterogenous mixture - colloidal solution and its properties suspensions and colloids mixtures

Smoke is an example of ?

  1. gas dispersed in liquid.

  2. gas dispersed in solid.

  3. solid dispersed in gas.

  4. solid dispersed in liquid.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Smoke is a collection of small and tiny unburned particles. It actually contains more of fumes and chemicals. The smoke is visible to us in form of ash and carbon. It is kind of solid particle present or dispersed in the gas.

Multiple choice chemistry nature of matter heterogenous mixture - colloidal solution and its properties suspensions and colloids mixtures

Zig-zag motion of the solute particle in a solution is known as :

  1. linear motion

  2. brownian motion

  3. circular motion

  4. curved motion
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is the random motion of particles suspended in a fluid resulting from their collision with the quick atoms or molecules in the gas or liquid. It is named after Robert Brown in 1827.

Multiple choice chemistry nature of matter heterogenous mixture - colloidal solution and its properties suspensions and colloids mixtures

Particles having size between 1 and 1000 nm dispersed in a medium is called a:

  1. colloid

  2. mixture

  3. suspension

  4. none of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A homogeneous looking heterogeneous mixture in which particles having a size between 1 and 1000 nm are dispersed in a continuous medium is called a colloid. Colloids are commonly called sols.


Hence. the correct answer is option $A$.

Multiple choice chemistry nature of matter heterogenous mixture - colloidal solution and its properties suspensions and colloids mixtures

The mixture in which one substance of microscopically dispersed insoluble particles is suspended throughout another substance is called _______.

  1. colloidal solution

  2. saturated solution

  3. unsaturated solution

  4. none of above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A colloid, in chemistry, is a mixture in which one substance of microscopically dispersed insoluble particles is suspended throughout another substance.
Examples of colloid are paint, milk, fog etc.

Multiple choice chemistry nature of matter heterogenous mixture - colloidal solution and its properties suspensions and colloids mixtures

Which of the following will form negatively charged colloidal solution?

  1. $100$ ml $0.1$M $AgNO _3+100$ ml $0.1$ M KI
  2. $100$ ml $0.2$M $AgNO _3+100$ ml $0.1$M KI
  3. $100$ml $0.1$M $AgNO _3+100$ ml $0.2$ M KI
  4. $100$ ml $0.2$M $AgNO _3+200$ ml $0.1$M KI
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

milli moles of $AgNO _3=100\times0.1=10$

milli moles of $KI=100\times.02=20$

$KI$ is in excess.

$AgI$ will be precipitated and excess $KI$ as $I^-$ ions will surround $AgI$ and form negative charged colloid.


Therefore, correct option is C.