You may suppose you have a 0.1 M solution of NH3, from:
NH4Cl + NaOH > NH3 + H2O.
Then you can compute the pH from the concentration of NH3 and its pKb.
The concentration is high enough to use the simplified formula:
[OH] = sqr(Kb*conc)
Cobalt has an atomic number of 27, which means that its atoms have 27 protons in their nuclei. In a neutral cobalt atom, there is also 27 electrons. The ground state<span>electron </span>configuration<span> of cobalt is [Ar]3d74s2 .</span>
10.9 because of mass= moles/mv it’s just basic chemistry