Question

write the formula for iron (iii) carbonate. *
your answer

this is a required question

name the compound: *
pb(no₃)₂.
your answer

write the name for (nh₄)₂cr₂o₇. *
your answer

give the formula for sulfurous acid. *
your answer

name the compound ni(oh)₂. *

Explanation:

• For iron (III) carbonate: Iron (III) has a charge of \(+3\) (\(Fe^{3+}\)), carbonate (\(CO_{3}^{2 -}\)) has a charge of \(- 2\). Using the criss - cross method (swap the magnitudes of the charges as sub - scripts), we get \(Fe_{2}(CO_{3})_{3}\).
• For \(Pb(NO_{3})_{2}\): \(Pb\) (lead) has a charge of \(+2\) (since there are two \(NO_{3}^{-}\) ions each with a charge of \(-1\)), and \(NO_{3}^{-}\) is the nitrate ion. So the name is lead (II) nitrate.
• For \((NH_{4})_{2}Cr_{2}O_{7}\): \(NH_{4}^{+}\) is the ammonium ion, and \(Cr_{2}O_{7}^{2 -}\) is the dichromate ion. So the name is ammonium dichromate.
• For sulfurous acid: The formula for sulfurous acid is \(H_{2}SO_{3}\) (where sulfur has an oxidation state of \(+4\)).
• For \(Ni(OH)_{2}\): \(Ni\) (nickel) has a charge of \(+2\) (since there are two \(OH^{-}\) ions each with a charge of \(-1\)), and \(OH^{-}\) is the hydroxide ion. So the name is nickel (II) hydroxide.

Answer:

• Iron (III) carbonate: \(Fe_{2}(CO_{3})_{3}\)
• \(Pb(NO_{3})_{2}\): Lead (II) nitrate
• \((NH_{4})_{2}Cr_{2}O_{7}\): Ammonium dichromate
• Sulfurous acid: \(H_{2}SO_{3}\)
• \(Ni(OH)_{2}\): Nickel (II) hydroxide