Question 1

Which of the following polyatomic ions is responsible for the purple color observed in potassium permanganate solutions?

Accepted Answer

$\mathrm{MnO_4^-}$

Question 2

A student is asked to write the formula for ammonium sulfate, a common fertilizer. Which of the following is correct?

Accepted Answer

$\mathrm{(NH_4)_2SO_4}$

Question 3

Which polyatomic ion is present in both sodium bicarbonate (baking soda) and in the buffer system of human blood?

Accepted Answer

$\mathrm{HCO_3^-}$

Question 4

Which of the following correctly matches the polyatomic ion with its formula?

Accepted Answer

Hydroxide: $\mathrm{OH^-}$

Question 5

A solution contains both $\mathrm{ClO_3^-}$ and $\mathrm{ClO_4^-}$. Which names correspond to these ions, respectively?

Accepted Answer

Chlorate and Perchlorate

Question 6

Which of the following ions has a $-2$ charge?

Accepted Answer

$\mathrm{SO_4^{2-}}$

Question 7

A patient is treated for cyanide poisoning. Which of the following is the correct formula for the cyanide ion?

Accepted Answer

$\mathrm{CN^-}$

Question 8

Which of the following compounds contains the dichromate ion?

Accepted Answer

$\mathrm{K_2Cr_2O_7}$

Question 9

Which of the following ions is a common ingredient in bleach and is responsible for its disinfecting properties?

Accepted Answer

$\mathrm{ClO^-}$

Question 10

Which of the following correctly represents the formula for hydrogen phosphate?

Accepted Answer

$\mathrm{HPO_4^{2-}}$

Question 11

A laboratory technician needs to prepare a buffer solution using a weak acid and its conjugate base. Which of the following pairs would be suitable?

Accepted Answer

Acetic acid ($\mathrm{CH_3COOH}$) and acetate ($\mathrm{C_2H_3O_2^-}$)

Question 12

Which of the following ions is amphiprotic, meaning it can act as both an acid and a base?

Accepted Answer

$\mathrm{HSO_4^-}$

Question 13

Which of the following ions is most likely to be found in a solution of hydrogen peroxide that has decomposed?

Accepted Answer

$\mathrm{O_2^{2-}}$

Question 14

A sample of water is found to contain both $\mathrm{NO_2^-}$ and $\mathrm{NO_3^-}$. What are the names of these ions?

Accepted Answer

Nitrite and Nitrate

Question 15

Which of the following ions is the conjugate base of dihydrogen phosphate ($\mathrm{H_2PO_4^-}$)?

Accepted Answer

$\mathrm{HPO_4^{2-}}$

Question 16

Which of the following ions is present in both Epsom salt and in the structure of DNA?

Accepted Answer

$\mathrm{SO_4^{2-}}$

Question 17

Which of the following ions would you expect to be present in a solution of sodium dichromate?

Accepted Answer

$\mathrm{Cr_2O_7^{2-}}$

Question 18

Which of the following ions is commonly used in the treatment of cyanide poisoning due to its ability to bind cyanide ions?

Accepted Answer

$\mathrm{S_2O_3^{2-}}$

Question 19

Which of the following ions is the conjugate acid of the carbonate ion ($\mathrm{CO_3^{2-}}$)?

Accepted Answer

$\mathrm{HCO_3^-}$

Common Polyatomic Ions in General Chemistry

Study Guide - Practice Questions