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$NaBr$ used to produce $AgBr$ for use in photography it can be prepared as

$\begin{matrix} Fe + {Br}_{2} & ⟶ & {FeBr}_{2} & --------- & (i) \\ {FeBr}_{2} + {Br}_{2} & ⟶ & {Fe}_{3} {Br}_{8} & --------- & (ii) \end{matrix}$

$\begin{matrix} {Fe}_{3} {Br}_{8} + {Na}_{2} {Co}_{3} & ⟶ & NaBr + {Co}_{2} + {Fe}_{3} O_{4} & --------- & (iii) \end{matrix}$

If yields of reaction $(ii)$ is $60 %$ and $(iii)$ is $70 %,$ then calculate the mass of iron required to produce $2.06 x 10^{3} kg NaBr$

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Important Questions on Some Basic Concepts of Chemistry

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Chemical Equations and Stoichiometry

A metal

M

(specific heat

0.16

) forms a metal chloride with

65 %

chlorine present in it. The formula of the metal chloride will be

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Chemical Equations and Stoichiometry

In an estimation of bromine by Carius method,

1.6 g

of an organic compound gave

1.88 g

AgBr

. The mass percentage of bromine in the compound is

\dots . .

(

Atomic mass,

Ag = 108, Br = 80 {gmol}^{- 1}

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Chemical Equations and Stoichiometry

1 g

of an organic compound containing

C

and

H

, on complete combustion produced

3.04 g

{CO}_{2}

and

1.53 g

H_{2} O

. Find the approximate percentage composition of

C

and

H

in the compound.

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Chemical Equations and Stoichiometry

When $0.15 g$ of an organic compound was analyzed using Carius method for estimation of bromine, $0.2397 g$ of $AgBr$ was obtained. The percentage of bromine in the organic compound is _________.(Nearest integer)

[Atomic mass : Silver $= 108,$ Bromine $= 80$ ]

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Chemical Equations and Stoichiometry

A sample of a hydrate of barium chloride weighing 61 g was heated until all the water of hydration is removed. The dried sample weighed 52 g. The formula of the hydrated salt is: (atomic mass, Ba = 137 amu, Cl = 35.5 amu)

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Chemical Equations and Stoichiometry

Complete combustion of

750 g

of an organic compound provides

420 g

{CO}_{2}

and

210 g

H_{2} O

. The percentage composition of carbon and hydrogen in organic compound is

15.3

and ______ respectively. (Round off to the Nearest Integer)

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Chemical Equations and Stoichiometry

Calculate the percentage by weight of oxygen in a mole of water?

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Chemical Equations and Stoichiometry

On complete combustion of

0.492 g

of an organic compound containing

C, H

and

O, 0.7938 g

{CO}_{2}

and

0.4428 g

H_{2} O

was produced. The

%

composition of oxygen in the compound is____. (Nearest Integer)

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Chemical Equations and Stoichiometry

An organic compound contains

C, H

and

S

. The minimum molecular weight of the compound containing

8 %

Sulphur is

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Chemical Equations and Stoichiometry

The percentage composition of carbon by mole in methane is:

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Chemical Equations and Stoichiometry

A protein '

A

' contains

0.30 %

of glycine (molecular weight

75

). The minimum molar mass of the protein '

A

' is____

\times 10^{3} g {mol}^{- 1}

[nearest integer]

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Chemical Equations and Stoichiometry

If the reaction sequence given below is carried out with $15$ moles of acetylene, the amount of the product $D$ formed (in $g$ ) is

Question Image

The yields of $A, B, C$ and $D$ are given in parentheses.

[Given: Atomic mass of $H = 1, C = 12, O = 16, Cl = 35$ ]

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Chemical Equations and Stoichiometry

$116 g$ of a substance upon dissociation reaction, yields $7.5 g$ of hydrogen, $60 g$ of oxygen and $48.5 g$ of carbon. Given that the atomic masses of $H, O$ and $C$ are $1, 16$ and $12$ , respectively. The data agrees with how many formulae of the following?

A. ${CH}_{3} COOH$

B. $HCHO$

C. ${CH}_{3} {OOCH}_{3}$

D. ${CH}_{3} CHO$

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Chemical Equations and Stoichiometry

In the crystalline solid

M S O_{4} \cdot n {II}_{2} O

of molar mass

250 g {mol}^{- 1},

the percentage of anhydrous salt is

64

by weight. The value of

n

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Chemical Equations and Stoichiometry

The complete combustion of

0.492 g

of an organic compound containing '

C

', '

H

' and '

O

' gives

0.793 g

{CO}_{2}

and

0.442 g

H_{2} O

. The percentage of oxygen composition in the organic compound is____.(nearest integer)

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Chemical Equations and Stoichiometry

The molecular formula of a commercial resin used for exchanging ions in water softening is

C_{8} H_{7} S O_{3} N a

(molecular weight = 206)

. What would be the maximum uptake of

C a^{2 +}

ions by the resin if expressed in

mol

per

gm

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Chemical Equations and Stoichiometry

A sample of

{NaClO}_{3}

is converted by heat to

NaCl

with a loss of

0.16 g

of oxygen. The residue is dissolved in water and precipitated as

AgCl

. The mass of

AgCl

(in

g

) obtained will be: (Given: Molar mass of

AgCl = 143 .5 g {mol}^{- 1}

)

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Chemical Equations and Stoichiometry

Complex A has a composition of

H_{12} O_{6} {Cl}_{3} C r

. If the complex on treatment with conc.

H_{2} {SO}_{4}

loses

13.5 %

of its original mass, the correct molecular formulas of

A

is:
[Given : atomic mass of

C r = 52

amu and

Cl = 35

amu]

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Chemical Equations and Stoichiometry

In Carius method of estimation of halogens,

250 mg

of an organic compound gave

141 mg AgBr

. What is the percentage of bromine in the compound (atomic mass of

Ag = 108

and atomic number of

Br = 80

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Chemical Equations and Stoichiometry

In the following reaction

Question Image

The $%$ yield for reaction $I$ is $60 %$ and that of reaction II is $50 %$ . The overall yield of the complete reaction is $%$

Important Questions on Some Basic Concepts of Chemistry

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