Assertion : In pressure-temperature $(P-T)$ phase diagram of water, the slope of the melting curve is found to be negative. Reason : Ice contracts on melting to water.

• Correct answer
  A

  If both assertion and reason are true and reason is the correct explanation of assertion
• B

  If both assertion and reason are true but reason is not the correct explanation of assertion
• C

  If assertion is true but reason is false
• D

  If both assertion and reason are false.

Solution

The negative slope is because of change of phase. This happens to liquids which contract on melting.

Hence, the correct answer is option: 'A'.