Answer:
hydrogen gas
Explanation:
Fuel cell vehicles use hydrogen gas to power an electric motor. Unlike conventional vehicles which run on gasoline or diesel, fuel cell cars and trucks combine hydrogen and oxygen to produce electricity, which runs a motor.
Answer:B) a reactant that undergoes reduction
Explanation:
Oxidation reaction is defined as the reaction in which a substance looses electrons. The oxidation state of the substance increases during oxidation.
Reduction reaction is defined as the reaction in which a substance gains electrons. The oxidation state of the substance gets reduced during reduction.

Overall reaction: 
The substance M which itself gets oxidized, reduces other and is called as reducing agent. The substance N which itself gets reduced, oxidizes other and is called as oxidizing agent.
Answer:
0.0845 M
Explanation:
First we <u>convert 4.27 grams of potassium iodide into moles</u>, using its <em>molar mass</em>:
- Molar Mass of KI = 166 g/mol
- 4.27 g ÷ 166 g/mol = 0.0257 mol
Now we <u>calculate the molarity of the solution</u>, using <em>the number of moles and the given volume</em>:
- Molarity = moles / liters
- Molarity = 0.0257 mol / 0.304 L = 0.0845 M