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

Answer the following in one or two sentences.

What is osmotic pressure?

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A solution concentration is expressed in molarity and not in molality while considering osmotic pressure. Why?

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Write the equation relating boiling point elevation to the concentration of the solution.

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What is the effect on the boiling point of water if 1 mole of methyl alcohol is added to 1 dm³ of water? Why?

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What are isotonic and hypertonic solutions?

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A solvent and its solution containing a nonvolatile solute are separated by a semipermeable membrane. Does the flow of solvent occur in both directions? Comment giving a reason.

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The osmotic pressure of CaCl₂ and urea solutions of the same concentration at the same temperature are respectively 0.605 atm and 0.245 atm, calculate van’t Hoff factor for CaCl₂.

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Explain reverse osmosis.

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How molar mass of a solute is determined by osmotic pressure measurement?

While considering boiling point elevation and freezing point depression a solution concentration is expressed in molality and not in molarity. Why?

Explain with diagram the boiling point elevation in terms of vapour pressure lowering.

A solution of citric acid C₆H₈O₇ in 50 g of acetic acid has a boiling point elevation of 1.76 K. If K_b for acetic acid is 3.07 K kg mol^-1, what is the molality of solution?

An aqueous solution of a certain organic compound has a density of 1.063 g mL^-1 , osmotic pressure of 12.16 atm at 25 °C and a freezing point of 1.03 °C. What is the molar mass of the compound?

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Which of the Na following is a buffer solution?

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The enthalpy of formation for all elements in their standard states is _______.

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How are basic buffer solutions prepared?

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If the standard enthalpy of formation of methanol is –238.9 kJ mol^–1 then entropy change of the surroundings will be _______. 

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Write one property of a buffer solution.

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Bond enthalpies of H–H, Cl–Cl, and H–Cl bonds are 434 kJ mol^–1, 242 kJ mol^–1, and 431 kJ mol^–1, respectively. Enthalpy of formation of HCl is _______.

Answer in brief.

Obtain the expression for work done in chemical reaction.