GSEB Standard 12 / Chemistry

Solutions

દ્રાવણો

The chapter examines ways to express concentration, factors affecting solubility, vapour pressure and colligative properties. Students should connect each formula with the physical quantity it measures and the assumptions under which it applies.

Learning objectives

Distinguish common concentration units.
Explain how temperature affects volume-based concentration.
Apply Raoult’s law to ideal solutions.
Use colligative properties to determine molar mass.

Important topics

Molarity and molality
Solubility
Vapour pressure
Ideal and non-ideal solutions
Colligative properties
Van’t Hoff factor

Useful question types

Conceptual concentration MCQs
Numerical concentration problems
Raoult’s law calculations
Reasoning questions about abnormal molar mass

Teacher tips

Make students state whether a concentration unit depends on mass or volume.
Check temperature assumptions before substituting values.
Require units in intermediate and final answers.

Limited public sample

Reviewed sample question

Which of the following concentration units is independent of temperature?

નીચેનામાંથી કયો સાંદ્રતાનો એકમ તાપમાનથી સ્વતંત્ર છે?

A
Molarity
મોલારિટી
B
Molality
મોલાલિટી
C
Normality
નોર્માલિટી
D
Volume %
કદ ટકાવારી

Show reviewed answer and explanation

Answer: B — Molality

Molality is based on the mass of solvent rather than the volume of solution. Mass does not change with temperature, so molality remains independent of temperature.

મોલાલિટી દ્રાવકના દળ પર આધારિત છે, દ્રાવણના કદ પર નહીં. દળ તાપમાન સાથે બદલાતું નથી, તેથી મોલાલિટી તાપમાનથી સ્વતંત્ર રહે છે.

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