HSC Science (Electronics) इयत्ता १२ वी - Maharashtra State Board Important Questions

The unit of rate constant for zero order reaction is _______.

(A) t^–1

(B) mol dm^–3 t^–1

(C) mol^–1 dm³ t^–1

(D) mol^–2 dm⁶ t^–1

Calcium carbonate used in the extraction of iron acts as _______.

(A) oxidising agent

(B) reducing agent

(C) gangue

(D) flux

Write the names and chemical formulae of any ‘two’ minerals of aluminium.

Mention the names of various steps involved in the extraction of pure metals from their ores.

Explain the following term

Flux

Which among the following reactions is an example of a zero order reaction?

a) `H_(2(g)) + I_(2(g)) -> 2HI_(g)`

b) `2H_2O_(2(l)) -> 2H_2O_(l) + O_(2(g))`

c) `C_12H_22O_(11(aq)) + H_2O_(l) -> C_6H_12O_(6(aq)) + C_6H_12O_(6(aq))`

d) `2NH_(3g)`   `N(2g) + 3H_(2(g))`

Which among the following minerals does NOT contain aluminium?

(a) Cryolite

(b) Siderite

(c) China clay

(d) Corundum

Explain the following methods to protect metals from corrosion:

Galvanization

Explain the following methods to protect metals from corrosion:

Passivation

Which one of the following oxidation state of Manganese is unstable?

(a) + 2

(b) + 4

(c) + 5

(d) + 7

In Van Arkel method of refining metal, impure zirconium is converted to unstable volatile
compound by heating it with _______.

(A) oxygen

(B) chlorine

(C) bromine

(D) iodine

Describe ‘froth floatation process’ for concentration of sulphide ore.

Write features of Ellingham's diagrams

The chemical formula of willemite is __

(a) ZnS

(b) ZnCO₃

(c) ZnO

(d) Zn₂SiO₄

The half-life period of zero order reaction A → product is given by

(a) `([A]_0)/k`

(b) `0.693/k`

(c) `[A]_0/(2k)`

(d) `(2[A]_0)/k`

Write the chemical equations involved in van Arkel method for refining zirconium metal.

What is the action of carbon on the following metal oxides:

Fe₂O₃ in the blast furnace

What is the action of carbon on the following metal oxides :

ZnO in the vertical retort furnace

In Van Arkel method for refining zirconium or titanium, the halogen used is __________.

The half life period of a first order reaction is 6. 0 h . Calculate the rate constant