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Questions Related to laboratory equipments

Fill in the blanks by choosing an appropriate option.
When sugar is dissolved in water, it undergoes a (i) change but if sugar is heated in a test tube over the Bunsen burner flame, it first melts, turns brown and finally turns (ii). The new substance formed is __(iii)_ and the change is a _(iv)_ change.

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  1. (i) - Physical reversible, (ii) - Black, (iii) - Charcoal, (iv) - Chemical irreversible

  2. (i) - Physical irreversible, (ii) - Black, (iii) - Coal, (iv) - Chemical irreversible

  3. (i) - Physical irreversible, (ii) - Red, (iii) - Charcoal, (iv) - Chemical reversible

  4. (i) - Physical reversible, (ii) - Red, (iii) - Coal, (iv) - Chemical reversible

Show answer
Correct Option: A
Explanation:

Dissolving sugar in water is a physical, reversible change. When sugar is heated, it decomposes into carbon and water (chemical reversible change).

$C _{12}H _{22}O _{11} \rightarrow       C    +    H _2O$
                                                        Carbon        (Steam)
                                                   

A salt gives a gas smelling rotten eggs with dilute HCl is :

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  1. sodium carbonate

  2. ferrous sulphide

  3. aluminium chloride

  4. silver nitrate

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Correct Option: B
Explanation:

Ferrous sulphide gives $H _2S$ gas with a smell of rotten eggs on an addition of dil. HCl.

A salt burns with apple green flame is:

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  1. sodium chloride

  2. potassium nitrate

  3. magnesium carbonate

  4. barium chloride

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Correct Option: D

If you keep red coloured marbles in a blue coloured vase made of glass then the colour of red coloured marbles will appear

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  1. Blue

  2. Red

  3. Black

  4. White

Show answer
Correct Option: C
Explanation:

When red coloured marbles are put inside the blue coloured vase, it will appear black because when light is incident on blue coloured vase which is transparent (Glass), it absorbs all the colours of white light except blue, and when blue colour tight incident on red marbles It will absorb blue colour and no light will be emitted by it. So it will appear black.


The ash which is collected after burning of magnesium ribbon is dissolved in water to give a solution X. What is the nature of the solution X when it is tested with indicators?

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  1. It turns blue litmus red and phenolphthalein pink, hence it is an acidic solution.

  2. It turns red litmus blue and phenolphthalein pink, hence it is an basic solution.

  3. It turns blue litmus red and gives no colour with phenolphthalein, hence it is an acidic solution.

  4. It does not change colour of red or blue litmus and phenolphthalein, hence it is a neutral solution.

Show answer
Correct Option: B,D
Explanation:

  $Mg         + O _2    \rightarrow     MgO $
Magnesium     Oxygen                    Magnesium
                                                        oxide (ash)
$MgO        +  H _2O   \rightarrow     Mg(OH) _2 $
  Magnesium   Water                         Magnesium
                                                           hydroxide
                                                             (X)

$MgO               + H _2O  \rightarrow   Mg(OH) _2$
Magnesium           Water                       Magnesium
oxide                                                       hydroxide
                                                                  (X)

Mg(OH)_2 solution is basic in nature which turns red litmus blue and phenolphthalein pink.

A solution of glucose received from some research laboratory has been marked mole fraction x and molality (m) at $1{ 0 }^{ \circ  }C$. When you will calculate its molality and mole fraction in your laboratory at $24^{ \circ  }C$ you will find:

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  1. mole fraction (x) and molality (m)

  2. mole fraction (2x) and molality (2m)

  3. mole fraction (x/2) and molality (m/2)

  4. mole fraction (x) and (m$ _{ - }^{ + } $dm) molality

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Correct Option: A
Explanation:

Molality and mole fractions both are independent of temperature . Therefore they will remain same after change of temperature.

Which one of the following commonly used in the laboratory in a filtration setup?

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  1. Balance

  2. Barometer

  3. Condenser

  4. Funnel

  5. Pipette

Show answer
Correct Option: D
Explanation:

Filtration is a technique that is used to either remoue solid impurites from an inorganic sdution or $two$ isolate an organic solid.

Thus, filtration setup involves a filter paper placed in a filter funnel. Therefore, funnel is used in filtration. A funnel is basically a tube or a pipe that is wide at the top and is narrow at the bottom. It is used for guiding a liquid or powder into into a small openning.

Which one of the following is used in the laboratory to transfer exact volume of liquid from one tube to another tube?

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  1. Balance

  2. Barometer

  3. Condenser

  4. Funnel

  5. Pipette

Show answer
Correct Option: E
Explanation:

$\rightarrow $ Pipette is a laboratory tool in chemistry to transfer exact volume of liquid from one tube to another.

$\rightarrow $ Balance is used to measure the weight of substance.
 $\rightarrow $ Barometer is used to measure atmospheric pressure.
$\rightarrow $ Condenser $\rightarrow $ used to cool hot gases into liquids.
$\rightarrow $ Funnel $\rightarrow $ used to remove fine particles from liquid using filter paper.

Select the correct statement.

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  1. Cation and anion are also called acidic or basic radicals, respectively

  2. Classification of anion is systematic as that of cation

  3. All the anions are deducted by soda extract solution without any exception

  4. None of these

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Correct Option: D
Explanation:

Option (D) is correct.
(A): Cation and anion are also called basic and acidic radicals, respectively.
(B): Classification of cation is systematic as that of anion.
(C): All the cations are deducted by soda extract solution without any exception.It is prepared to prevent the cation in interfering when we do the anion analysis.

The phenomenon in which white transparent crystal changes into white powder is called :

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  1. Deliquescence

  2. Efflorescence

  3. Allotropy

  4. Sublimation

Show answer
Correct Option: B
Explanation:

Efflorescence is a phenomenon in which white transparent crystal changes into a white powder. Efflorescences can occur in natural and built environments. On porous construction materials it may present a cosmetic problem only, but can sometimes indicate serious structural weakness.