HSC Science (General) 12th Standard Board Exam - Maharashtra State Board Question Bank Solutions

Write the formulae of the raw materials used for preparation of Dextran.

For a certain reaction, ∆H = − 50 kJ and ∆S = − 80 J K^-1, at what temperature does the
reaction turn from spontaneous to non-spontaneous?

(A) 6.25 K

(B) 62.5 K

(C) 625 K

(D) 6250 K

What is the action of heat on potassium permanganate?

Define activation energy.

Calculate activation energy for a reaction of which rate constant becomes four times when temperature changes from 30 °C to 50 °C. (Given R = 8.314 JK⁻¹ mol⁻¹). 

The Zieglar-Natta catalyst is used in the preparation of _______.

(A) LDPE

(B) PHBV

(C) PAN

(D) HDPE

Write observed electronic configuration of elements from first transition series having half
filled d-orbitals.

Write the structure of melamine.

Write applications of co-ordination compounds in medicine and electroplating.

Derive the equation : W = - P_extAV

Write features of Ellingham's diagrams

Explain why Mn²⁺ ion is more stable than Mn³⁺? (Given : Mn→ Z=25)

Write balanced chemical equations for action of potassium permanganate on Warm conc. sulphuric acid

What is the action of acidified potassium dichromate on - KI 

An antifertility drug is -

(a) Novestrol

(b) Histamine

(c) Vernal

(d) Equanil

Explain only reaction mechanism for alkaline hydrolysis of tert-butyl bromide

What are oxides?  Write different types of oxides with one example each.

Define the following terms : 
a. Cryoscopic constant
b. Resistivity 

Represent a cell consisting of Mg²⁺ | Mg half cell and Ag⁺
 | Ag half cell and write the cell reaction.
( `"E"_("Ag")^° = 0.799 "V", "E"_("Mg")^° = - 2.37 "V"`)

5 moles of helium expand isothermally and reversibly from a pressure 40 × 10^-5  N m^-2 to 4 × 10^-5 N m^-2  at 300 K. Calculate the work done, change in internal energy and heat absorbed during the expansion. (R = 8.314 J K^-1  mol^-1).