Answer:- 13.6 L
Solution:- Volume of hydrogen gas at 58.7 Kpa is given as 23.5 L. It asks to calculate the volume of hydrogen gas at STP that is standard temperature and pressure. Since the problem does not talk about the original temperature so we would assume the constant temperature. So, it is Boyle's law.
Standard pressure is 1 atm that is 101.325 Kpa.
Boyle's law equation is:

From given information:-
= 58.7 Kpa
= 23.5 L
= 101.325 Kpa
= ?
Let's plug in the values and solve it for final volume.

On rearranging the equation for 

= 13.6 L
So, the volume of hydrogen gas at STP for the given information is 13.6 L.
1) C !! Physical Process
2) A
3) D !! Water is universal solvent !
if you need any explanation ; comment !!
Quantum numbers are used to describe the location of electrons in atoms.
Principal quantum number(n) tells which energy shell the electrons reside in.
The first energy shell n = 1, second energy shell n = 2 and it goes on.
Azimuthal quantum number (l) states which orbital the electron is most likely to reside in. the number of orbitals in an energy shell depends on the principal quantum number. number of orbitals are from 0 to n-1
If l = 0, s orbital
l = 1 , p orbital
l = 2, d orbital
in 2nd energy shell the number of orbitals are 0,1 etc.
5s-
Principal quantum number n = 5
Azimuthal quantum number l = 0
6p
Principal quantum number n = 6
Azimuthal quantum number l = 1
4d
Principal quantum number n = 4
Azimuthal quantum number l = 2
One of the things that Revolution causes is seasons