IGCSE Biology Paper-1: Specimen Questions with Answers 187 - 187 of 208

Question 187



The diagram shows an experiment on diffusion.

Concentration of Sugar in Solution X

More water diffuses out of the bag than diffuses in.

What is the concentration of sugar in solution X?


Choice (4)


40 %


10 %


30 %


20 %




  • Diffusion is the net movement of molecules or ions of a given substance from a region of higher concentration to lower one by virtue of their kinetic energy.
  • Phenomenon of diffusion can be observed every day.
  • It may occur between gas and gas (e. g. , diffusion of ammonia into air) , liquid and liquid (e. g. , diffusion of alcohol into water) , or solid and liquid (e. g. , diffusion of sugar into water) . The diffusion of one matter is dependent on other. That is why many gases and solutes diffuse simultaneously and independently at different rates in different direction at the same place and time, without interfering each other. From soil, water, and ions of simple inorganic salts pass into plants through the root cells by a process which is diffusion, though greatly modified by other factors. The water and solutes pass through the dead and living vessels and from cell to cell by diffusion. When a crystal of copper sulphate is placed in a beaker containing water, a dense blue colour is seen around the crystal.
Concentration of Sugar in Solution X