It can block light. Please mark Brainliest!!!
ANSWER IS (A)
EXPLANATION:
Bronsted-Lowry concept states that a substance is an acid if it can act as a H+ donor.
HCl in aqueous solution means that HCl is present in water, HCl + H2O --> H3O+ + Cl-. This reaction will take place, the H+ from HCl will be donated to H2O. So, HCl is a bronsted-lowry acid by definition.
However, Methanol (CH3OH) its written that it is liquid, i.e. pure methanol, CH3OH(l). It is both acidic as well as basic. when it is mixed with water then it behaves as an acid.
The last one ammonia in gas phase is also neutral because its not in water. if mixed in water it behaves as a base.
Among the choices, the polyatomic ion is only the third choice, NH4+ where it is composed of nitrogen one atom of nitrogen and 4 atoms of hydrogen. Choice 2 is a monoatomic atom being composed only of calcium. Then, the first and fourth choices are not ions because they are not charged.