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What are examples of primary standards?

Important Questions on Some Basic Concepts of Chemistry

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Volumetric Calculations

A solution of sodium sulphate contains

92 g

{Na}^{+}

ions per kilogram of water. The molality of

{Na}^{+}

ions in that solution in

mol {kg}^{- 1}

is:

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Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Volumetric Calculations

A gas mixture contains

25 %

He

and

75 % {CH}_{4}

by volume at a given temperature and pressure. The percentage by mass of methane in the mixture is approximately ___ .

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Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Volumetric Calculations

Molality

(m)

18 M H_{2} {SO}_{4}

is, approximately [

d = 1.84 g {cm}^{- 3}

, Molar mass of

H_{2} {SO}_{4} = 98 g {mol}^{- 1}

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Volumetric Calculations

The number of water molecules in

250 m L

of water is closest to [Given, density of water is

1.0 g m L^{- 1}

; Avogadro's number

= 6.023 \times 10^{23}]

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Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Volumetric Calculations

Dissolving 120 g of a compound of (mol. wt. 60) in 1000 g of water gave a solution of density 1.12 g/mL. The molarity of the solution is :

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Volumetric Calculations

$5.00 mL$ of $0.10 M$ oxalic acid solution taken in a conical flask is titrated against $NaOH$ from a burette using phenolphthalein indicator. The volume of $NaOH$ required for the appearance of permanent faint pink colour is tabulated below for five experiments. The concentration, in molarity, of the $NaOH$ solution is $xM$ .

Exp. No.	Vol. of $NaOH$ $(mL)$
$1$	$12.5$
$2$	$10.5$
$3$	$9.0$
$4$	$9.0$
$5$	$9.0$

What is the value of $100 x$ ?

Round of your answer to the nearest integer.

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Volumetric Calculations

While combusting in air,

4 g

H_{2}

gas was completely converted into water. If

36 μmole

{CO}_{2}

from air is dissolved into that water, what is the concentration of

{CO}_{2}

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Volumetric Calculations

What is mole fraction of the solute in a

1.00

m aqueous solution?

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Volumetric Calculations

The mole fraction of a solvent in aqueous solution of a solute is

0.8 .

The molality (in mol

{k g}^{- 1}

) of the aqueous solution is:

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Volumetric Calculations

What would be the molality of 20% (mass/mass) aqueous solution of

K I

? (molar mass of

K I = 166 g m o l^{- 1}

)

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Volumetric Calculations

Which of the following is dependent on temperature?

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Volumetric Calculations

8 g

NaOH

is dissolved in

18 g

H_{2} O

. Mole fraction of

NaOH

in solution and molality (in

mol {kg}^{- 1}

) of the solution respectively are:

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Volumetric Calculations

What is meant by primary and secondary standards in volumetric analysis?

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Volumetric Calculations

Potassium Dichromate $(K_{2} {Cr}_{2} O_{7})$ is suitable to be used as a primary standard.

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Volumetric Calculations

1 mole of N₂ and 4 mole of H₂ are allowed to react in a sealed container and after the reaction some water is introduced in it. The aqueous solution formed required 1 L of 1 M HCl for neutralization. The mole fraction of the gaseous product in the mixture after the reaction was

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Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Volumetric Calculations

Calculate the percentage composition in terms of mass of a solution obtained by mixing