Answer: The correct option is 1.
Explanation: Endothermic reactions are the reactions in which heat is provided to break down the reactant molecules.
In option 1:
The stronger intermolecular forces between the particles in solid molecule are broken down to convert into gaseous form. Hence, some energy in the form of heat is provided to move them far apart. Therefore, it is considered as an endothermic reaction.
In option 2, 3 and 4:
All the other processes involves the formation of bonds and thus there is no need to provide any energy.
between two oppositely charged ions
The first reaction is a synthesis reaction (A+B -> AB)
1.Start with the number of grams of each element, given in the problem.
2.Convert the mass of each element to moles using the molar mass from the periodic table.
3.Divide each mole value by the smallest number of moles calculated.
4.Round to the nearest whole number. This is the mole ratio of the elements and is.
