The Combination with water is also pretty nice:
HCl (Hydrochloric Acid - Very dangerous) NaOH (Caustic Soda - Also very dangerous)
Combine to literal Saltwater (H2O and NaCl).
Interestingly, because the reaction goes both ways, in any amount of salt water, there will be a miniscule amount of Hydrochloric Acid and Caustic Soda. The concentration is so low because they immediately react again, going back to water and salt.
Very yes.