The number of protons in the nucleus of the atom is equal to the atomic number (Z). The number of electrons in a neutral atom is equal to the number of protons. The mass number of the atom (M) is equal to the sum of the number of protons and neutrons in the nucleus.
<u>Answer:</u> The concentration of
comes out to be 0.16 M.
<u>Explanation:</u>
To calculate the concentration of acid, we use the equation given by neutralization reaction:

where,
are the n-factor, molarity and volume of acid which is 
are the n-factor, molarity and volume of base which is NaOH.
We are given:

Putting values in above equation, we get:

Hence, the concentration of
comes out to be 0.1862 M.
Out of
the following given choices;
A. increasing
the pH of the salt.
B. increasing
the surface area of the salt.
C. increasing
the pressure of the salt.
<span>D. increasing
the temperature of the salt.</span>
The answer is B. When a substance is reduced to smaller
sizes, its surface area to volume ratio increases. Therefore crushing barium
salts to smaller particles increase the surface area on which it reacts with
the acid. This consequently increases the rate of speed of the reaction.
I think it’s I
Iodine has 53 protons and 74 neutrons