A polyatomic ion, also known as a molecular ion, is a charged chemical species (ion) composed of two or more atoms covalently bonded or of a metal complex that can be considered to be acting as a single unit. The prefix poly- means "many," in Greek, but even ions of two atoms are commonly referred to as polyatomic
The answer is A because if you place the first two numbers 1 and 3
Au=2
S=3
H=6
It has to equal to the product so then you put in the last two numbers 2 and 3
Au=2
S=3
H=6
pH of buffer can be calculated as:
pH=pKa+log[salt]/[Acid]
As ka = 4.58 x 10-4
Concentration of [Salt] that is NO2(-1)=0.380M
Concentration of [Acid] that is HNO2=0.500M
So, pH= -log(4.58*10^-4)+log((0.380)/0.500))
=3.21
So pH of solution will be 3.21
