In a double-replacement reaction,
the reactants are usually a metal and a nonmetal
one of the reactants is often water
energy in the form of heat or light is often produced
the reactants are generally two ionic compounds in aqueous solution

The correct answer is D: the reactants are generally two ionic compounds in aqueous solution.

Explanation:

A type of reaction in which two reactants participate and exchange ions with each other as the reaction proceeds. Such type of reaction is known as a double displacement reaction. In double displacement reaction, the product formed is precipitate.

Below is the pathway of the double displacement reaction:

AB + CD → AD + CB

In double displacement reaction usually, ionic compounds are involved. The bond formation between the reacting species may be ionic or covalent in nature.

the equation that correctly represent the reaction for formation of ammonia is

n2+ 3h2 → 2nh3 (answer d)

1 mole of nitrogen gas (n2) react with 3 moles of hydrogen gas (h2) to form 2 moles of ammonia ( nh3). this is in a process known as haber process were iron is used as a catalyst and reaction take place that a higher temperature and pressure. the process is exothermic hence energy is released.

is it a purebred? it looks more like a red nose, but it doesn't have the red could it be a staffordshire bull terrior? unsure if that's the right name for it sorry