Section Test:Acids and Bases

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Easy Questions (<30 seconds each!)


1. What colour does litmus paper change when put in a pH 4 solution?

red
yellow
green
blue
→ In an acidic solution litmus paper changes red, in basic solutions it changes blue. The other answers are distractions.

2. What is the pOH of a solution whose pH is 3 at 25C?

2
4
11
13
→ The pOH of a solution can be easily found from the pH by simply subtracting the pH from 14. In general pH + pOH = 14, but this is only true at 25C. (Why?)

3. How many moles of HCl will neutralize 4 moles of Sodium Hydroxide?

2
4
6
8
→ Sodium Hydroxide is a base, NaOH, with a normality of 1, therefore, it is a one to one ratio of acid to base when neutralizing, thus 4 moles of OH- would require 4 moles of H+

4. Which of the following compounds is polyprotic?

HBr
Ca(OH)2
BF3
H2SO4
→ A polyprotic compound simply means that it is an acid capable of donating more than one hydronium ion, H2SO4 has two.

5. What is the pH a solution whose hydronium ion concentration is 0.0001 moles per liter?

1
2
4
8
→ the pH of a solution is the -log of the concentration of hydronium ions (H+), 0.0001 is 10-4, thus the pH is 4.

Medium Questions


6. If 6 milliliters of 1M HCl is exactly neutralized by 3 milliliters of KOH then what is the molarity of the KOH?

2M
3M
6M
9M

7. A weak acid (HX) has an equilibrium constant of 1.0 X 10-8. What is the pH of a 1.0 M solution of this acid?

1
4
7
8

8. Which could act as either a Brønsted acid or a Brønsted base?

chloride ion
sulfide ion
bisulfide ion
carbonate ion
→ When H2S dissociates it becomes HS-, this however can dissociate again into S2-. Therefore, HS-, or bisulfide can either gain or lose an electron in acid/base reactions.

9. Which of the following is the weakest Brønsted acid?

HBr
HI
HCl
HF

10. Which 0.1M aqueous solution is the best conductor of electricity?

C2H5OH
HCl
H2SO4
NH3

11. When K2CO3 dissolves in water the resulting solution turn litmus paper?

red and is acidic
blue and is acidic
red and is basic
blue and is basic

12. A 40 milliliter sample of HCl is completely neutralized by 10 milliliters of a 2.0M basic solution. What is the molarity of the HCl solution?

0.1M
0.25M
0.5M
1.0M

13. Which metallic ion would produce an acid solution when in water?

sodium
aluminum
potassium
lithium

14. The titration of a strong acid and a weak base could result in which pH at the equivalence point?

6
7
9
10

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