The correct answer is B. The magnifying lens is a converging lens. It focuses the incoming light to one single point. It can be proved when you use the magnifying glass to burn a piece of paper. You can observe that the light will concentrate at a single point.
Answer: 0.028 grams
Explanation:
Depression in freezing point :
Formula used for lowering in freezing point is,
or,
where,
= change in freezing point
= freezing point constant (for benzene} =
m = molality
Putting in the values we get:
0.028 grams of DDT (solute) must be dissolved in 209.0 grams of benzene to reduce the freezing point by 0.400°C.
NaHCO3 is the right answer