Question

Beckmann's thermometer measures:
A.Boiling point of the solution
B.Freezing point of the solution
C.Any temperature
D.Elevation in boiling point (or) depression in freezing point.

Answer 1

We need to remember that a Beckmann thermometer is a gadget used to quantify little contrasts of temperature, however not total temperature values. Today its utilization has highly been supplanted by electronic thermometers. It was discovered by Ernst Otto Beckmann, a German scientist.

Complete answer:
We must know that a Beckmann thermometer's length is normally $40 - 50cm$. The temperature scale commonly covers around ${5^ \circ }C$ and it is separated into hundredths of a degree. With a magnifier it is conceivable to appraise temperature changes to ${0.001^ \circ }C$. The scope of temperatures estimated with such a thermometer is dictated by the measure of mercury in the reservoir and capillary of the thermometer. The quirk of Beckmann's thermometer configuration is a reservoir at the upper terminal of the cylinder, by methods for which the amount of mercury in the bulb could be expanded or reduced with the goal that the instrument can be set to gauge temperature contrasts at one or the other high or low temperature values. Conversely, the scope of a normal mercury-in-glass thermometer is fixed, being set by the adjustment marks carved on the glass or the imprints on the printed scale.
German scientist Ernst Otto Beckmann discovered Beckmann's thermometer for measuring the colligative properties. So we can say. Beckmann’s thermometer is used to determine the boiling point elevation (or) freezing point depression.
Therefore, the option (D) is correct.

Note:
We have to remember that the Beckmann thermometers are utilized in lab practice for calorimetry and for estimations close to near phase transition points, yet their utilization is diminishing. In simple words, only change in temperature could be measured using Beckmann thermometer and temperature could not be measured using Beckmann’s thermometer.