The directions in the candy recipe for pralines instruct the cook to remove the pot containing the candy mixture from the heat when the candy micture reaches the soft-ball stage. the soft ball stage corresponds to the temperature of 236°f. after the soft ball stage is reached ,the pecans and vanilla are added. can a celsius thermometer with a range of -10°c be used to determine when the soft ball stage is reached in the candy micture? why or why not?

A Celsius thermometer with a range of -10°C cannot be used to determine when the soft ball stage is reached in the candy mixture.  

Temperature is most commonly measured with a thermometer that has two different scales: Fahrenheit and Celsius. Water freezes at 0°C and boils at 100°C on the Celsius scale and freezes at 32°F and boils at 212°F on the Fahrenheit scale.

Temperature of 236°F corresponds to 113.3°C. Now a Celsius scale has a maximum of 100°C on the thermometer. Hence a Celsius thermometer cannot be used to measure a temperature that corresponds to 236°F.