Reactions rates for reactions occurring in solution can be increased by increasing the concentration of the solution. with gases you can do something similar, which is to -

The table lists the lattice energies of some compounds. compoundlattice energy (kj/mol)lif            –1,036licl            –853naf            –923kf            –821nacl            –786which statement about crystal lattice energy is  best  supported by the information in the table? the lattice energy increases as cations get smaller, as shown by lif and kf. the lattice energy increases as the cations get larger, as shown by lif and licl. the lattice energy decreases as cations get smaller, as shown by nacl and naf. the lattice energy decreases as the cations get smaller, as shown by naf and kf.