Joke Collection Website - Joke collection - "The sodium metal in the laboratory is on fire, and the water is almost used up ..." How to explain this joke?

"The sodium metal in the laboratory is on fire, and the water is almost used up ..." How to explain this joke?

If sodium metal catches fire, put out the fire with water.

Sodium reacts with water, which will replace hydrogen atoms in water to generate hydrogen and give off heat. Hydrogen will burn, and the fire will be bigger.

2Na+2 H2O = H2+2 NaHO+ heat (the chemical formula seems to be like this).

I think the punchline should be understood like this.