All of the statements about nuclear reactions are true except nuclear reactions involve changes in the nucleus of an atom. a nuclear reaction is unaffected by the chemical state of the atoms involved. nuclear reactions of the same element vary according to which isotope is involved. the rate of a nuclear reaction is increased by the addition of a catalyst. energy changes in nuclear reactions are much greater than in ordinary chemical reactions.

the rate of a nuclear reaction is increased by the addition of a catalyst.

Explanation:-

Catalysts are substances that increase the speed of ordinary chemical reactions. Ordinary chemical reactions involve electrons. But a nuclear reaction involves only the nucleus. Hence catalysts cannot increase the rate of a nuclear reaction.

The chemical state of the atom depends on the electrons of the atom. Hence a nuclear reaction is unaffected by the chemical state of the atoms involved.

Isotopes have different mass number. So the nucleus is different. Hence nuclear reactions of the same element vary according to which isotope is involved.

In nuclear reactions energy release is given by E= mc where c is the speed of light. Hence energy changes in nuclear reactions are much greater than in ordinary chemical reactions.