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Subject Test Chemistry

Question 6 of 13

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The set of lettered choices below refers to multiple questions. Select the one lettered choice that best fits each statement or answers each question. A choice may be used once, more than once, or not at all in each set.

Reacts with an equal volume of 0.05 text   end text M space text Ba(OH) end text text end text subscript 2 to form a solution with text pH end text equals 7

Select an Answer

0.1 text   end text M space text HCl end text

Correct Answer: 
Yes

0.1 text   end text M space text NaCl end text

Correct Answer: 
No

0.1 text   end text M space text HC end text subscript 2 text H end text subscript 3 text O end text subscript 2

Correct Answer: 
No

0.1 text   end text M space text CH end text subscript 3 text OH end text

Correct Answer: 
No

0.1 text   end text M space text KOH end text

Correct Answer: 
No

To answer this question, you need to know that acids react with bases to form salts and water. Since the question refers to equal volumes of each solution, assume 1 liter of each solution is available. Barium hydroxide solution is a strong base (i.e., it is completely ionized in water) and 1 liter of 0.05 space M space text Ba(OH) end text text end text subscript 2 provides 0.1 mole of text OH end text to the power of minus ions in solution. When 1 liter of this solution is added to 1 liter of either 0.1 text   end text M space text NaCl end text, 0.1 text   end text M space text CH end text text end text subscript 3 text OH end text or 0.1 text   end text M space text KOH end text, no reactions occur and the resulting solutions remain basic; that is, the text pH end text will be greater than 7 in each case. When 0.1 mole of text OH end text to the power of minus ions reacts with 0.1 mole of acetic acid, the resulting solution will also be basic and have a text pH end text greater than 7 because acetic acid is a weak acid (i.e., it is incompletely ionized in water). The acetic acid reacts with the text OH end text to the power of minus ions as follows:

text HC end text subscript 2 text H end text subscript 3 text O end text subscript 2 plus text OH end text to the power of minus leftwards arrow with rightwards arrow on top text C end text subscript 2 text H end text subscript 3 text O end text subscript 2 text end text to the power of minus plus text H end text subscript 2 text O end text

The acetate ion produced is a strong base, which hydrolyzes in water to yield a solution containing more text OH end text to the power of minus ions than text H end text to the power of plus ions. When 1 liter of 0.05 space M space text Ba(OH) end text text end text subscript 2 reacts with 1 liter of 0.1 text   end text M space text HCl end text, there is a reaction between 0.1 mole of text OH end text to the power of minus ions and 0.1 mole of text H end text to the power of plus to form 0.1 mole of text H end text text end text subscript 2 end subscript text O end text. The resulting solution contains text Ba end text to the power of 2 plus end exponent ions and text Cl end text to the power of minus ions and equal concentrations of text OH end text to the power of minus and text H end text to the power of plus ions. The solution formed is neutral and the text pH end text is 7; therefore choice (A) is the correct answer.

Question Difficulty: 
hard