The formation of a gas in a chemical reaction, due to ions changing places, often indicates that the reaction is which type?
a) synthesis

b) double-displacement

c) decomposition

d) single-displacement

The correct answer is D.

Explanation: In a chemical reaction, when there is changing of ions taking place and is leading to the formation of a gas can be considered as a single displacement reaction.

Single-Displacement reactions are defined as the reactions in which a higher reactive metal displaces a lower reactive metal. This is in reference to the reactivity series.

Hydrogen lies below in the reactivity series and when the higher reactive metal displaces hydrogen from a chemical reaction, it leads to the formation of hydrogen gas.

Example:

the correct answer is b. a strong acid completely dissociates to its ions when dissolved in water. completely dissociates to and ions. a is incorrect because does not fully ionize to and ions and some remain as the compound . c and d are incorrect because, and do not fall into the category of bronsted lowry acids. a bronsted lowry acid is a proton donor and since both molecules do not have a proton to donate they are not bronsted lowry acids. likewise,   if we use the lewis acid definition, they cannot be acids. a lewis acid is an electron pair acceptor. both and have a complete octet so can not accept any electrons which disqualifies them as acids.