What are Acid Base and Salt?

The name acid has been derived from the Latin word “acidus” which means sour. You must have experienced a number of foods which taste sour, like lemons, oranges, grapes and many others. Lemons have citric acid and ascorbic acid is found in oranges. You will be thrilled to know that your body also produces hydrochloric acid in stomach which helps in digestion of food. You can check yourself if something has acid in it or not by simply putting it on a litmus paper. If the paper turns red that means it has acid. Acid changes the colour of litmus paper to red. 

As everything has its counterpart, acid also has its counterpart which is named as Base. It tastes bitter. Baking soda, washing soda are common examples of bases. If you try a litmus paper test, a base will turn it into blue. And when acid and base come together they cancel the effect of each other and thus salt comes into existence. Table salt is the most abundant salt in the nature.

What are acid base and salt?

How can we define an acid and a base? Initially scientist Svante Arrhenius gave a theory which is named after him the Arrhenius theory. According to it acids are those substances which give hydrogen ion when dissolved in water.

HX_(aq) ⟶  H⁺ + X^-_(aq)

H⁺ is very reactive and can’t live alone so it combines with O of H₂O and forms H₃O⁺ ion, it is called hydronium ion. I have used X with H which represents halogens group 17 elements, but why? Think about it.

HX_(aq) + H₂O_(aq) ⟶  H₃O⁺ _(aq) + X^-_(aq)

And bases are the substances which give OH^- ion when dissolved in water.

MOH_(aq) ⟶ M⁺ + OH^-_(aq)

Here I have used M with OH and it represents metals of group 1, think about it too. Arrhenius theory fits well in this case, but it is limited to the aqueous solutions only. It doesn’t explain acidic or basic behaviour of substances lacking H⁺ or OH^-ions. Like ammonia NH₃ which is a base but doesn’t have OH^-ion.

In the next post we will see what solutions have been given by the scientists for such problems.

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