Heat of sublimation of Li(s) = 166 kJ/mol Bond energy of HCl = 427 kJ/mol
Ionization energy of Li(g) = 520. kJ/mol
Electron affinity of Cl(g) = -2349 kJ/mol
Lattice energy of LiCl(s) = -2829 kJ/mol
Bond energy of H₂ = -432 kJ/mol
Calculate the net change in energy for the following reaction:
2Li(s) + 2HCl(g) --> 2LiCl(s) + H₂(g)

answer: option (b) is the correct answer.

explanation:

a covalent bond is formed by sharing of electrons. whereas polarity arises due to difference in electronegativity of two atoms.

therefore, more is the electronegativity of an atom which combines with the titanium, more readily it will induce a partial positive and negative charge.

thus, out of the given options fluorine is most electronegative and has an incomplete octet. therefore, it will readily combine with titanium to share the electrons and complete its octet.  

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.