Some Basic Concepts of Chemistry Test

Result

Some Basic Concepts of Chemistry Test - 78

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Weekly Quiz Competition

Question 1
1 / -0

How many tons of $$Zn$$ can be obtained form 10 tons of $$ZnS$$?

A
5.025

B
10.487

C
15.282

D
None of these

Solution
Question 2
1 / -0

Avogadro number is the number of molecule present in

A
1 lit of any gas at NTP

B
10 lit of any gas at NTP

C
11.2 lit of any gas at NTP

D
22.4 lit of any gas at NTP
Question 3
1 / -0

A 10 mg effervescent tablet containing sodium bicarbonate and oxalic acid releases 0.25 ml of $${ CO }_{ 2 }$$ at T= 298.15 K and P=1 bar. If molar volume of $${ CO }_{ 2 }$$ is 25.0 L under such condition, what is the percentage of sodium bicarbonate in each tablet?

A
16.8

B
8.4

C
0.84

D
33.6
Question 4
1 / -0

1.2 gm of carbon is burnt completely in oxygen (limited supply) to produce CO and $${ C }O_{ 2 }.$$ This mixture of gases is treated with solid $${ I }_{ 2 }{ O }_{ 5 }$$ (to know the amount of CO produced), the liberated iodine required 120 ml of 0.1 M hypo solution for complete titration. The % of carbon converted into CO is:

A
70%

B
100%

C
50%

D
30%

Solution
Question 5
1 / -0

What is the percentage of lead in lead pencil ?

A
$$25$$

B
$$50$$

C
$$75$$

D
None of these

Solution
Question 6
1 / -0

An impure sample of silver (1.5 g) is heated with S to form 0.214 g of $${ Ag }_{ 2 }S$$. What was the percent yield of $${ Ag }_{ 2 }S$$?

A
21.6 %

B
7.2 %

C
1.7 %

D
24.8 %

Solution
Question 7
1 / -0

A mixture of ethane and neon having a volume of 20ml requires 49 ml of oxygen for complete combustion. The percentage of ethane in the mixture is:

A
70 %

B
30 %

C
35 %

D
64 %

Solution
Question 8
1 / -0

The law which suggests $$n_1 = n_2$$ for two solutions at same temperature and pressure is

A
van't Haff - avogadro's law

B
van't Hoff Boyle's law

C
van't Hoff's law

D
Henry's law

Solution
Question 9
1 / -0

When burnt in air, $$14.0\ g$$ mixture of carbon and sulphur gives a mixture of $$CO_2$$ and $$SO_2$$ in the volume ratio of $$2:1$$, volume being measured at the same conditions of temperature and pressure. Moles of carbon in the mixture is __________.

A
$$0.25$$

B
$$0.40$$

C
$$0.5$$

D
$$0.75$$

Solution

Consider the mass of $$C=x$$

mass of $$S=14-x$$

moles of $$C=\dfrac {x}{12};$$ moles of $$\dfrac {14-x}{32}$$

$$C+O_2\to CO_2;\quad S+O_2\to SO_2$$

moles of $$C=$$ moles of $$CO_2=\dfrac {x}{12}\quad $$ moles of $$S=$$ moles of $$SO_2=\dfrac {14-x}{32}$$

Given,

$$\dfrac {V_c}{V_s}=\dfrac {2}{1}$$

$$V\alpha $$ no. of mole

$$\dfrac {\dfrac {x}{12}}{\dfrac {14-x}{32}}=\dfrac {2}{1}$$

$$\dfrac {x}{12}\times \dfrac {32}{14-x}=\dfrac {2}{1}$$

$$\dfrac {4x}{42-3x}=1$$

$$4x=42-3x$$

$$7x=42$$

$$\boxed {x=6}$$

$$\therefore \ $$ moles of $$C$$ in mixture $$=\dfrac {w}{M}=\dfrac {6}{12}=0.5$$

Answer is option $$C$$
Question 10
1 / -0

If you are given Avogadro's number of atoms of a gas $$X$$. If half of the atoms are converted into $${X}_{(g)}$$ by energy $$\Delta H$$. The IE of $$X$$ is

A
$$\cfrac{2\Delta H}{{N}_{A}}$$

B
$$\cfrac{2{N}_{A}}{\Delta H}$$

C
$$\cfrac{\Delta H}{2{N}_{A}}$$

D
$$\cfrac{{N}_{A}}{\Delta H}$$

Solution