how can know acidity or basicity of a solution without using any PH measure?

Question

I know this sound abit lame...
you see NaOH = Sodium hydroxide by looking this formant and the element table can you tell the if this is a acid or basic? I'm not very sure?

it is basic solution.
If you really don't know the NaOH solution?

other then that how can we determine H+ Cl−
acid or basic solution abort the + & -?

2 more question
why basic solution eat glass and it doesn't eat plastic?
Why Acid solution eat plastic/rubber and it doesn't eat glass?

Answer 1

as dear chill said it is the no. of H+ and OH-
but there are some other defenitions 4 acidsand basis,e.g.
one who has a nonbonding pair of electron is acid the othe who has a blank orbital that accepts this pair is base.
acids are sour but basis are bitter.
and so on...
they r just defenitions!

Answer 2

acidity of a baseis the number of hydrogen ions present in a base while bacisity of an acid is number of hydroxide ions in an acid. try applying this rule,u will find it.