Answer:
The equation to show the the correct form to show the standard molar enthalpy of formation:
Explanation:
The standard enthalpy of formation or standard heat of formation of a compound is the change of enthalpy during the formation of 1 mole of the substance from its constituent elements, with all substances in their standard states.
Given, that 1 mole of 
gas and 1 mole of 
liquid gives 2 moles of HBr gas as a product.The reaction releases 72.58 kJ of heat.
Divide the equation by 2.
The equation to show the the correct form to show the standard molar enthalpy of formation:
Density decreases that's why ice floats on water because it's less dense than water.
Answer: Option (B) is the correct answer.
Explanation:
Surface tension is defined as the attractive forces experienced by the surface molecules of a liquid by the molecules present beneath the surface layer of the liquid.
And, viscosity is defined as the ability of a liquid to resist its flow. When a substance has high viscosity then it is known as a viscous substance.
Since, it is given that viscosity of liquid B is more than liquid A. Therefore, liquid B has more resistive force on its surface as compared to liquid A. As a result, time taken by liquid B is more than time taken by liquid A.
Also, Surface tension = 
Surface tension of liquid B is more than liquid A. Therefore, 
.
Thus, we can conclude that tA will be less than tB.
