Couldn't get your doubt.

Isn't 50 milliliters plural (as indicates by an -s at the end of milliliter)? were is plural to match with the plural subject.

My confusion is I don't understand when to consider mililiters as plural or fifty mililiters as majority or collective noun. Excuse me if i am asking very simple doubts, but it is better to get one's basics right.

Thanks for your time and help.

Right.

1 milliliter is singular

x milliliters is always plural. (where x>1) This is valid for all units of measurement in general.

You can look at how -s has been added at the end of milliliter to indicate that the subject is to be considered plural.

@Ruchi, Nicksworth

A number - takes a plural (A number of men are ...........)

The number - takes singular (The number of boys is .........)

The five milliliters I think is tricky business!!

It depends on the context if it was added in one shot as a whole, I am almost inclined to say it is singular - "Five milliliters was added ..........."

However, if it was added one drop at a time or a milliliters at a time then we could say "Five milliliters were added ..........."

mj78ind wrote:
The five milliliters I think is tricky business!!

It depends on the context if it was added in one shot as a whole, I am almost inclined to say it is singular - "Five milliliters was added ..........."

However, if it was added one drop at a time or a milliliters at a time then we could say "Five milliliters were added ..........."

Hmmm, I can't think how 5 milliliters can ever be singular.

And the context you mention may not necessarily be available.

Consider the original sentence posted here -
Fifty milliliters of sodium chloride were added in the second step of the experiment.

Do we know whether the addition was done in one go or drop by drop? How do we decide whether the subject is singular or plural in this sentence?