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

Gold occurs as face centred cube and has a density of 19.30 kg dm^-3. Calculate atomic radius of gold. (Molar mass of Au = 197)

What are hormones?

Define complex lipids

Face centred cubic crystal lattice of copper has density of 8.966 g.cm^-3. Calculate the volume of the unit cell. Given molar mass of copper is 63.5 g mol^-1 and Avogadro number N_A is 6.022 x 10²³ mol^-1

Write a note on the self oxidation-reduction reaction of an aldehyde with a suitable example.

Write names and chemical formulae of monomers used in preparing Buna-S.

Mention 'two' functions of lipids

An element crystallises in a b.c.c lattice with cell edge of 500 pm. The density of the element is 7.5g cm^-3. How many atoms are present in 300 g of the element?

Following reactions occur at cathode during the electrolysis of aqueous silver chloride solution :

`Ag^+(aq)+e^(-)rarrAg(s)" ""      ""       "E^@=+0.80V`

`H^+(aq)+e^(-)rarr1/2H_2(g)" "" "" " E^@=0.00V`

On the basis of their standard reduction electrode potential (E°) values, which reaction is feasible at the cathode and why ?

3.9 g of benzoic acid dissolved in 49 g of benzene shows a depression in freezing point of 1.62 K. Calculate the van't Hoff factor and predict the nature of solute (associated or dissociated).

(Given : Molar mass of benzoic acid = 122 g mol⁻¹, K_f for benzene = 4.9 K kg mol⁻¹)

An element with molar mass 27 g mol⁻¹ forms a cubic unit cell with edge length 4.05 ✕ 10⁻⁸ cm. If its density is 2.7 g cm⁻³, what is the nature of the cubic unit cell?

Calculate Δ_rG^° for the reaction 

Mg (s) + Cu²⁺ (aq) → Mg²⁺ (aq) + Cu (s)

Given : E^°_cell = + 2.71 V, 1 F = 96500 C mol^–1

Describe the following:

Cannizzaro reaction

Write any ‘two’ advantages of calomel electrode.

Arrange the following oxyacids of chlorine - HClO, HClO₂, HClO₃, and HClO₄ with respect to increasing order of thermal stability.

The secondary structure of protein is determined by _______.

(A) co-ordinate bond

(B) ionic bond

(C) hydrogen bond

(D) covalent bond

Write names and chemical formulae of monomers used in preparing Buna-N.

Explain optical activity of lactic acid

Explain with reason sign conventions of ΔS in the following reaction

N_2(g) + 3H_2(g) → 2NH_3(g)

Explain with reason sign conventions of ΔS in the following reaction

CO_2(g) → CO_2(g)