Answer:
-3
Explanation:
The oxidation state or oxidation number of an atom is the total number of electrons that an atom either gains or loses in order to form a chemical bond with another atom.
The complex anion here is [Cr(CN)6]3-.
Now, as the oxidation state of CN or cyanide ligand is -1, and if we suppose the oxidation state of Cr to be 'x', then; x - 6 = -3 (overall charge on the anion),
so x= +3. Hence the oxidation state of Chromium in this complex hexacyanochromium (III) anion comes out to be -3.
.
Answer: 1
Explanation: Lithium has a single electron in the second principal energy level, and so we say that lithium has one valence electron.
The volume of concentrated HCl : 2.073 ml
<h3>Further explanation</h3>
Given
37% HCl by mass; density 1.19 g/mL
Required
The volume of concentrated HCl
Solution
Conversion to molarity :
37% x 1.19 g/ml =0.4403 g/ml
g/ml to mol/L :
=0.4403 g/ml x 1000 ml/L : 36.5 g/mol
=12.06 mol/L
or we can use formula :

Dilution formula :
M₁V₁=M₂V₂
12.06 M x V₁ = 0.1 M x 0.25 L
V₁ = 0.0021 L = 2.073 ml