HSC Science (Computer Science) 12th Standard Board Exam - Maharashtra State Board Question Bank Solutions for Chemistry

When acetaldehyde is treated with dilute NaOH, the following reaction is observed.

\[\begin{array}{cc}
\ce{2CH3 - CHO ->[dil.NaOH] CH3 - CH - CH2 - CHO}\\
\phantom{...............}|\\
\phantom{.................}\ce{OH}
\end{array}\]

1. What are the functional groups in the product?
2. Can another product be formed during the same reaction? (Deduce the answer by doing atomic audit of reactant and product).
3. Is this an addition reaction or condensation reaction?

Heat of combustion of methane is - 890 kJ/mol. On combustion of 12 gm of methane in excess of oxygen, ______ heat is evolved.

For the reaction, aA + bB → cC + dD, write the expression for enthalpy change of reaction in terms of enthalpies of formation of reactants and products.

The enthalpy of combustion of S (rhombic) is − 297 kJ mo1^-1. Calculate the amount of sulphur required to produce 29. 74 kJ of heat.

Define the term common ion effect. Explain with suitable example.

Draw energy profile diagram and show:

1. activated complex
2. energy of activation for forward and backward reactions
3. enthalpy of reaction

The heat evolved in the combustion of 6.022 x 10²¹ carbon particles is 3.94 kJ. The heat of combustion of carbon is ______.

For the reaction, H₂ + I₂ ⇌ 2HI; ΔH = 12.4 kcal. The heat of formation of HI, ΔH_f = ______.

NICAD storage cell is made up of ______ electrodes.

Calculate Δ_subH of the H₂O from the given data:
\[\ce{H2O_{(s)}->H2O_{(l)},}\] Δ_fusH = 6.01kJ mol⁻¹

\[\ce{H2O_{(l)}-> H2O_{(g)},}\] Δ_VapH = 45.07 kJ mol⁻¹.

Prove that: M₂ = `(W_2RT)/(πV)`.

Calculate heat evolved for combustion of 13 gm of acetylene (C₂H₂).

Given: \[\ce{C2H2_{(g)} + 5/2O_{2(g)}-> 2CO_{2(g)} + H2O_{(l)} \Delta_{(c)}H^{0} = - 1300 kJ}\]

Arrange the following solutions in the order of increasing osmotic pressure (π) assuming complete ionization.

1. 0.5M Li₂ SO₄
2. 0.5M KCl
3. 0.5M Al₂ (SO₄)₃ 
4. 0.1 M BaCl₂

Heat of combustion of CH_4(g) is -890 kJ/mole. What is the value of Δ_c H of 8gm of methane?

Define reverse osmosis.

Name the four colligative properties that are oftently used for determination of molecular mass.

Write a note on the aldol condensation reaction of acetaldehyde.

What is aldol condensation? Explain it with suitable examples.

Draw a neat labelled diagram of a lead accumulator.

Discuss the trends in electronegativity and atomic radii for elements of group 16 17, 18.