Chemistry Test 273

Result

Chemistry Test 273

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
4 / -1

A metal in a compound can be displaced by another metal in the uncombined state. Which metal is a better reducing agent in such a case?

A
Better reducing agent is the one that looses more electrons

B
Better reducing agent is the one that looses less electrons

C
Both are same in reducing capacity

D
The reduced metal is a better reducing agent than the reducing metal

Solution

Concept of Reducing Agent:

A reducing agent is a substance that loses or "donates" an electron to another substance in a redox chemical reaction. Therefore, a good reducing agent is the one that gets oxidized easily, or in other words, the one that can easily lose electrons.

Characteristics of a Good Reducing Agent:

Electron Loss: A better reducing agent is the one that loses more electrons. This is because by losing electrons, the reducing agent gets oxidized and in turn reduces the other substance. This is the basic principle of a redox reaction.

Reactivity: The reactivity of the metal also determines its capacity as a reducing agent. Metals that are high in the reactivity series are good reducing agents. This is because they can easily lose electrons and get oxidized.

Stability: Metals that are less stable are better reducing agents because they can easily lose electrons to attain a stable state.

Hence, Option A is the correct answer - a better reducing agent is the one that loses more electrons.
Question 2
4 / -1

In which case change of oxidation number of V is maximum?

A

B

C

D
Equal in each case

Solution
Question 3
4 / -1

The oxidation number of P in Ba(H₂PO₂)₂, Ba(H₂PO₃)₂ and Ba(H₂PO₄)₂ are respectively

A
+ 1, + 2, + 3

B
+ 3, + 2, + 1

C
+ 1, + 3, + 5

D
+ 2 in all

Solution
Question 4
4 / -1

A
zero BM

B

C

D

Solution
Question 5
4 / -1

Which is chlorate (I) ion?

A
ClO₂^-

B
ClO₃^-

C
ClO₄^-

D
ClO^-

Solution

ClO₃^-: A very reactive inorganic anion.

The term chlorate can also be used to describe any compound containing the chlorate ion, normally chlorate salts.

Example: Potassium chlorate, KClO₃
Question 6
4 / -1

How much heat will be required at constant pressure to form 1.28 kg of CaC₂ from CaO(s) & C(s) ?

Given :

Δ_fH°(CaO, s) = -152 kcal/mol

Δ_fH°(CaC₂, s) = -14 kcal/mol

Δ_fH°(CO, g) = -26 kcal/mol

A
+112 kcal

B
224 kcal

C
3840 kcal

D
2240 kcal

Solution
Question 7
4 / -1

The enthalpy of neutralisation of a weak acid in 1 M solution with a strong base is -56.1 kJ mol^-1. If the enthalpy of ionization of the acid is 1.5 kJ mol^-1 and enthalpy of neutralization of the strong acid with a strong base is -57.3 kJ equiv^-1, what is % ionization of the weak acid in molar solution (assume the acid to be monobasic) ?

A
10

B
15

C
20

D
80

Solution

The correct answer is option C

Ideally, the enthalpy of neutralization should be - 57.3 K.J + 1.5 K.J = - 55.8 KJ.

But it is - 56.1 KJ.
Question 8
4 / -1

From the following data, the heat of formation of Ca(OH)_2(s) at 18°C is ………..kcal:

A
-98.69

B
-235.43

C
194.91

D
98.69

Solution

The correct answer is Option B.

Ca_(s) + O2_(g) + H2_(g)→ Ca(OH)₂ , ΔHf = ?

Desired equation = eq (iii) + eq(i) - eq (ii)

ΔH_f = (−151.80)+(−15.26)−(−68.37)

ΔH_f = (-151.80)+(-15.26)-(-68.37)

ΔH_f = −235.43KCalmol⁻¹
Question 9
4 / -1

The pK_a of a weak acid, HA, is 4.80. The pK_b of a weak base, BOH, is 4.78. The pH of an aqueous solution of the corresponding salt, BA, will be -

A
4.79

B
7.01

C
9.22

D
9.58

Solution
Question 10
4 / -1

How many litres of water must be added to litre of an aqueous solution of HCl with a pH of 1 to create an aqueous solution with pH of 2?

A
2.0 L

B
9.0 L

C
0.1 L

D
0.9 L

Solution

That means the volume of water added to the original solution of 1 L = 10 −1 = 9 L