HSC Science (General) 12th Standard Board Exam - Maharashtra State Board Important Questions

Calculate the e.m.f. of the following cell at 298 K:

Fe(s) | Fe²⁺ (0.001 M) | | H⁺ (0.01 M) | H₂(g) (1 bar) | Pt(s)

Given that \[\ce{E^0_{cell}}\] = 0.44 V

[log 2 = 0.3010, log 3 = 0.4771, log 10 = 1]

Calculate emf of the following cell at 25°C:

\[\ce{Sn/Sn^2+ (0.001 M) || H+ (0.01 M) | H2_{(g)} (1 bar) | Pt_{(s)}}\]

Given: \[\ce{E^\circ(Sn^2+/sn) = -0.14 V, E^\circ H+/H2 = 0.00 V (log 10 = 1)}\]

Define the Standard enthalpy of combustion.

Three moles of an ideal gas are expanded isothermally from 15 dm³ to 20 dm³ at a constant external pressure of 1.2 bar. Calculate the amount of work in Joules.

For a reaction A + B ⟶ P, the rate is given by

Rate = k [A] [B]²

How is the rate of reaction affected if the concentration of B is doubled?

For a reaction A + B ⟶ P, the rate is given by

Rate = k [A] [B]²

What is the overall order of reaction if A is present in large excess?

Distinguish between Order and Molecularity of reaction.

Explain pseudo-first-order reaction with an example.

Describe the manufacturing of H₂SO₄ by the contact process.

Elements of group 16 have lower ionization enthalpy values compared to those of group 15 elements. Explain why?

[NiCl₄]²⁻ is paramagnetic, while [Ni(CO)₄] is diamagnetic, though both are tetrahedral. Why? (Atomic number of Ni = 28)

Define racemic mixture.

What is the elasticity of demand?

Distinguish between the following.

Standard coins and Token coins.

Distinguish between Surplus budget and Deficit budget.

What is the elasticity of demand?

Distinguish between Surplus budget and Deficit budget.

Distinguish between the following concepts:

Public Finance and Private Finance

Distinguish between internal debt and external debt.

(A) Read the following extract and answer the questions given below :
Oil is one of the world's major sources of energy. We depend on it as fuel for heating, transport, and generation of power.
For centuries, animal and vegetable oils have been used for cooking and as a source of artificial light. But it is mineral oil which meets most of the world's needs today.
Crude mineral oil comes out of the earth as a thick brown or black liquid with a strong smell. It is a complex mixture of many different substances, each with its own individual qualities. Most of them are combinations of hydrogen and carbon in varying proportions. Such hydrocarbons are also found in other forms such as bitumen, asphalt and natural gas. Mineral oil originates from the carcasses of tiny animals and from plants that live in the sea. Over millions of years, these dead creatures form large deposits under the sea bed and ocean currents cover them with a blanket of sand and silt. As this material hardens, it becomes sedimentary rock and effectively shuts out the oxygen so preventing the complete decomposition of the marine deposits underneath. The layers of sedimentary rock become thicker and heavier. Their pressure produces heat, which transforms the tiny carcasses into crude oil in a process that is still going on today.
The earth's crust is split into a few hu·ge continental plates which move continuously rather like rafts on a sluggish tide. Geologists call this rnoven1ent as 'continental drift'.

(1) What does the extract ·tell us about?

(2) In which form does crude mineral oil come out of the earth and from what does it originate?

(3) How is 'continental drift' formed?

(4) According to you, how can we stop the excessive use of energy?

(5) Rewrite the following sentences in the ways instructed :
(i) Oil is one of the world's major sources of energy.
(Rewrite it as a negative sentence without changing its meaning.)

(ii) As this material hardens, it becomes sedimentary rock.
(Make it a compound sentence.)

(iii) Geologists call this movement 'con·tinental drift'.
(Frame a 'Wh-question' to get the underlined part as an answer.)

(6) Give the antonyms from the extract for :
(i) artificial
(ii) lighter

(B) Write·a brief summary of the above extract with the help of the points given below and suggest a suitable title.
Oil as a source of energy - our dependence - types of oil -mineral oil origin of crude oil formation of crude oil-farming of sedimentary rocks - continental drift