A true solution is a homogeneous mixture of solute and solvent. Chalk powder in water is a heterogenous mixture. Is it a true solution?

No, chalk powder in water is not a true solution.

A true solution is a homogeneous mixture in which solute particles are uniformly dissolved throughout the solvent but chalk powder in water is insoluble and not uniformly distributed throughout the solvent (water). Moreover, the solid particles of chalk in water are large enough to be seen by naked eyes. These all are the properties of a suspension. Thus we can say that chalk powder in water is a suspension.

(Suspension: it is a heterogenous mixture of small insoluble particles in a solvent which can be clearly seen by eyes.

Homogenous solution: it is a mixture in which composition of solute is uniform throughout the solvent.

Heterogenous solution: it is a mixture in which composition of solute is not uniform throughout the solvent.)