Hydrogen Test

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Hydrogen Test - 45

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Weekly Quiz Competition

Question 1
1 / -0

Name the phenomenon used in dissolution of water.

A
solubility

B
crystallization

C
polarization

D
surface tension
Solution
Solubility is the property of a solid, liquid or gaseous chemical substance called solute to dissolve in a solid, liquid or gaseous solvent.
Factors that affect the solubility-
Physical and chemical properties of solute and solvent,
Temperature
Pressure
Presence of other chemical
The extent of the solubility of a substance in a specific solvent is measured as the saturation concentration, where adding more solute does not increase the concentration of the solution and begins to precipitate the excess amount of solute.
Question 2
1 / -0

Calculate the ebullioscopic for water. The heat of vapourisation is $$40.685 \ kJ\ mol^{-1}$$.

A
$$0.512\ K\ kg\ mol^{-1}$$

B
$$1.86\ K\ kg\ mol^{-1}$$

C
$$5.12\ K\ kg\ mol^{-1}$$

D
$$3.56\ K\ kg\ mol^{-1}$$

Solution

$$K_b = \dfrac{MRT_b\times T_b}{1000\times DH_v}$$

$$K_b =\dfrac{18\times 8.314\times 273\times 273}{1000\times 40.685\times 1000}$$

$$K_b= \dfrac{20820933.108}{40.685\times 1000000}$$
$$K_b=0.512$$ M is molecular mass of water $$T_b$$ is boiling point of water
Question 3
1 / -0

Out of the following metals which will give $$H_2$$ reaction with $$NaOH$$?
$$I: Zn$$
$$II: Mg$$
$$III: Al$$
$$IV: Be$$

A
$$I, II, III, IV$$

B
$$I, III, IV$$

C
$$II, IV$$

D
$$I, III$$

Solution

The reactions of following metals with $$NaOH$$ can be given as:-
$$Zn+2NaOH\longrightarrow Na_2ZnO_2+H_2$$
$$Mg+2NaOH\longrightarrow 2Na+Mg(OH)_2$$
$$2Al+2NaOH+2H_2O\longrightarrow 2NaAlO_2+3H_2$$
$$Be+NaOH+H_2O\longrightarrow Na_2[Be(OH)_4]+H_2$$
From the above reactions, it is clear that $$Zn,Al$$ and $$Be$$ react with $$NaOH$$ to give $$H_2$$ while $$Mg$$ does not.
Question 4
1 / -0

Which of the hydrated species can exist?
I. $$H_5O^+_2$$
II. $$H_3O^+$$
III. $$H_3O^-_2$$
IV. $$H_7O^+_3$$
Select alternate from.

A
II only

B
I and II

C
I, II and IV

D
I, II, III and IV

Solution

Water on self ionization form $$H_3O^+$$. Water in strong acid also lead to the formation of $$H_5O_2^+$$, $$H_7O_3^+$$ and water in strong alkali also lead to the formation of $${H_3O_2}^-$$. So all the hydrated species can exist.
Question 5
1 / -0

Industrial hydrogen is manufactured by passing an electric current through a solution of?

A
Alumina

B
Sodium hydroxide

C
Carbon dioxide

D
Magnesium hydroxide

Solution

Electrolysis of $$NaOH$$ gives hydrogen $$A^{+}$$ cathode

$$Na^{+}+e^{-}\rightarrow Na$$

At anode

$$20H^{-}\rightarrow H_{2}+O_{2}+2e^{-}$$
Question 6
1 / -0

Which of the following is not true about $${ H }_{ 2 }O$$ molecule?

A
The molecule has $$\mu =0$$

B
The molecule can act as a base

C
Shows abnormally high boiling point in comparison to hydrogen oxygen group

D
The molecule has a bent shape

Solution

Solution:- (A) The molecule has $$\mu = 0$$.

The dipole moment of water is $$1.85 D$$.

The dipole moment arises because oxygen is more electronegative than hydrogen; the oxygen pulls in the shared electrons and increases the electron density around itself.

This creates an electric dipole moment vector, with the partial negative charge on the oxygen atom.

There are two $$O-H$$ bonds, so the dipole moment of the molecule is the resultant vertical vector projection of the individual diagonal dipole vectors.

Hence, (A) is not true.
Question 7
1 / -0

The sources of dissolved oxygen in water is ________.

A
photosynthesis

B
natural aeration

C
mechanical aeration

D
all of the above

Solution

Oxygen dissolves into the water from two sources one from the atmosphere and other from the plants in the water. The primary source of oxygen for a pond is from microscopic algae. By using the sunlight these produce oxygen by a process called photosynthesis and thereby release oxygen into the pond water.
Question 8
1 / -0

Which of the following cannot be oxidized by $$H_2O_2$$?

A
$$KI + HCl$$

B
$$O_3$$

C
$$PbS$$

D
$$Na_2SO_3$$
Question 9
1 / -0

Hydrogen exists in atomic state in which of the following compounds?

A
Metallic hydrides

B
Ionic Hydride

C
Molecular hydrides

D
$${ H }_{ 2 }O$$
Solution
- Metal hydrides are metals which have been bonded to hydrogen to form a new compound. Any hydrogen compound that is bonded to another metal element can effectively be called a metal hydride. Generally, the bond is covalent in nature, but some hydrides are formed from ionic bonds.
- Hence option A is a correct answer.
Question 10
1 / -0

$$H_2$$ gas can not be prepared by :

A
$$Be$$ $$+$$ $$NaOH$$

B
$$Na$$ $$+$$ $$NaOH$$

C
$$Mg$$ $$+$$ $$NaOH$$

D
both A and B

Solution

For (A):- $$Be+NaOH\longrightarrow Na_2BeO_2+H_2$$

For (B):- $$Na+NaOH\longrightarrow Na_2O+H_2$$

For (C):- $$Mg+2NaOH\longrightarrow Mg(OH)_2+2Na$$

From the above three reactions, it can be concluded that (A) and (B) react with $$NaOH$$ to give $$H_2$$ gas but (C) does not give $$H_2$$ gas.

Therefore, option D is correct.

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Hydrogen Test - 45

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Hydrogen Test - 45

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SHARING IS CARING

Question 1

solubility

crystallization

polarization

surface tension

Solution

Question 2

$$0.512\ K\ kg\ mol^{-1}$$

$$1.86\ K\ kg\ mol^{-1}$$

$$5.12\ K\ kg\ mol^{-1}$$

$$3.56\ K\ kg\ mol^{-1}$$

Solution

Question 3

$$I, II, III, IV$$

$$I, III, IV$$

$$II, IV$$

$$I, III$$

Solution

Question 4

II only

I and II

I, II and IV

I, II, III and IV

Solution

Question 5

Alumina

Sodium hydroxide

Carbon dioxide

Magnesium hydroxide

Solution

Question 6

The molecule has $$\mu =0$$

The molecule can act as a base

Shows abnormally high boiling point in comparison to hydrogen oxygen group

The molecule has a bent shape

Solution

Question 7

photosynthesis

natural aeration

mechanical aeration

all of the above

Solution

Question 8

$$KI + HCl$$

$$O_3$$

$$PbS$$

$$Na_2SO_3$$

Question 9

Metallic hydrides

Ionic Hydride

Molecular hydrides

$${ H }_{ 2 }O$$

Solution

Question 10

$$Be$$ $$+$$ $$NaOH$$

$$Na$$ $$+$$ $$NaOH$$

$$Mg$$ $$+$$ $$NaOH$$

both A and B

Solution

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