Answer:- 
Explanations:- The solution we have is a buffer solution and we know that a buffer solution resists a change in its pH if a strong acid or base is added to it.
Here, the buffer solution we have is of a weak base and it's conjugate acid. So, a strong acid(nitric acid) is added to this buffer then it reacts with the base present in the buffer so that the acid could be neutralized. This is called buffer action.
The net ionic equation is written as:

Note that
is a strong acid and nitrate ion is the spectator ion so it is not included in the net ionic equation.
Answer:
Electrons are transferred between atoms together in the ionic compound. The ions are arranged in a regular repeating pattern in an ionic crystal
Explanation:
Answer : The energy of the photon emitted is, -12.1 eV
Explanation :
First we have to calculate the
orbit of hydrogen atom.
Formula used :

where,
= energy of
orbit
n = number of orbit
Z = atomic number of hydrogen atom = 1
Energy of n = 1 in an hydrogen atom:

Energy of n = 2 in an hydrogen atom:

Energy change transition from n = 1 to n = 3 occurs.
Let energy change be E.

The negative sign indicates that energy of the photon emitted.
Thus, the energy of the photon emitted is, -12.1 eV
Answer:
A chemical reaction occurs when reactants are converted into products. A chemical equation is a representation of a chemical reaction using chemical symbols. The chemical equation also indicates the physical state of the reactants and products. The substances that go into a chemical reaction are called the reactants, and the substances produced at the end of the reaction are known as the products.
Explanation: because UwU