[guest43533]

First, I am a science beginner.

I know that sulphuric acid a very strong acid.

If, tons of sulphuric acid is spilt into a lake, then I guess the lake would be acidified..

Then, how can I neutralise the sulphuric acid in water?

(Sorry, I am not sure that I used proper scientific words or not...)

[Bored chemist]

Add a few tons of limestone.
- of course, if the lake is in a limestone area the water won't stay acid for long- it will react.

[syhprum]

How toxic is sulphuric acid ? To what degree should it be diluted so that I could drink a few liters a day

[Bored chemist]

Sulphuric acid dissociates in water to form sulphate ions and hydrogen ions.
The sulphate ions are practically harmless in this context- the worst they would do is upset your stomach a bit.
So the question is how acidic can drinking water be and not be toxic.
Well, rainwater is naturally slightly acidic, it contains about 10 µg of hydrogen ions per litre.
You would get that from about 500 µg of sulphuric acid per litre.

This site
[ edit: dratted url won't copy]
Tells me there's 172 mg of phosphorus in a litre of cola.
That's about 1/ 180 moles and it will carry 3 times that number of hydrogen ions with it.
Something like 0.017 grams of hydrogen per litre equivalent to  about 50 times that much sulphuric acid.

Nearly a gram of sulphuric acid per litre.

However, even drinking cola type drinks is associated with a significant risk of damage to your teeth, so you probably want to keep the concentration well below that.

The sensible answer is, of course, as low as you can manage.

[Kryptid]

Any kind of base will work so long as you add enough of it.

[Bored chemist]

Using calcium carbonate has the advantages that
it's cheap
An excess of it isn't likely to do much harm because it's not soluble
The by-product, calcium sulphate, is also not very soluble so it's unlikely to do much harm.

I'd love to know why the OP asked this.

[evan_au]

To what degree should it be diluted so that I could drink a few liters a day

Some doctors suggest drinking 2 liters of water per day.
I suggest that you drink the 2l of water, and leave out the sulphuric acid.

After all, your stomach naturally produces hydrochloric acid to help with digesting food. You don't need any more acid than this (Ok, maybe a bit of abscorbic acid to provide your tiny vitamin C intake).

See: https://en.wikipedia.org/wiki/Gastric_acid

[Bored chemist]

Incidentally, if you find yourself in some situation where the only "drinking" water available contains significant sulphuric acid, you would be better off filtering it through crushed limestone before drinking it.

[entropy970]

A very simplified consideration:

Acid Dissociation Constant
HA(aq) ⇌ H+(aq) + A-(aq)
K(a) = [H+(aq)][A-(aq)] / [HA(aq)]
pH = -log[H+]
.
If you know the dissociation constant (search online), as well as the concentration of the other entities (measure it yourself), then you would be able to calculate the concentration of [H+(aq)].

According to the definition of pH, the pH is given by 1 / log[H+]. The pH of water, in general, at a temperature of 298K, is approximately 7.

Various fruit juices are acidic, and we drink them with knowledge of potential teeth corrosion. And, due to homeostasis, favorable conditions within the body, including the pH of contents, are generally maintained. However, there is obviously an upper limit for which such is beyond your body's abilities and/or capabilities. And there is a difference between drinking fruit juices, and drinking HCl (which has a corrosive effect on human tissue), for example.