Which of the following is not a double-replacement? a.) hno3 (aq) + kho (aq) -> h2o (l) + kno3 (aq)b.) ba(oh)2 (aq) + 2hclo4 (aq) -> ba(clo4)2 (aq) + 2h2o (l)c.) naoh (aq) + hcl (aq) -> h2o (aq) + nacl (s)d.) zn (s) + 2hcl (aq) -> h2 (g) + zncl2 (s)

The correct answer is option D.

Explanation:

From the given options the reaction which is not a double replacement reaction is:

This because the above reaction is an example of single replacement reaction.

Whereas;

Double replacement reaction is a type of chemical reaction in which exchange of ions among the reactants take place.

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.