Answer:-A. It is less than 890 kJ/mol because the amount of energy required to break bonds is less than the amount of energy released in forming bonds.
Explanation: Endothermic reactions are defined as the reactions in which energy of the product is greater than the energy of the reactants. The total energy is absorbed in the form of heat and 
for the reaction comes out to be positive.
Exothermic reactions are defined as the reactions in which energy of the product is lesser than the energy of the reactants. The total energy is released in the form of heat and for the reaction comes out to be negative.
In the formation of new bonds more energy is released than is required to break the existing bonds, heat is released.
In the formation of bonds less energy is released than is required to break the existing bonds, heat is absorbed.
First, we write the reaction equation:
2KI + PbNO₃ → K₂NO₃ + PbI₂
The molar ratio of KI to PbNO₃ is 2 : 1
Moles of PbNO₃ present:
Moles = concentration (M) x volume (dm³)
= 0.194 x 0.195
= 0.038
Moles of KI required = 2 x 0.038 = 0.076 moles
concentration = moles / volume
volume = moles / concentration
= 0.076 / 0.2
= 0.38 L = 380 ml
NH3 is soluble in water because it has the same amount of intermolecular forces as water. NH3 is a polar molecule and water is a polar molecule so they dissolve each other. NCl3 does not dissolve in water because it is a nonpolar molecule which is different with water. NCl3 is nonpolar due to the difference in electronegativities between 3 atoms of Cl and 1 atom if N2.
