Class 10 Exam > Class 10 Questions > Assertion : pH = 7 signifies pure water.Reaso...
Start Learning for Free
Assertion : pH = 7 signifies pure water.
Reason : At this pH, [H+] = [OH-]= 10-7.
- a)Assertion (A) is false but reason (R) is true.
- b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
- c)Assertion (A) is true but reason (R) is false.
- d)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
- e)Both Assertion and Reason are false.
Correct answer is option 'D'. Can you explain this answer?
Most Upvoted Answer
Assertion : pH = 7 signifies pure water.Reason : At this pH, [H+] = [O...
Let's evaluate the assertion and reason provided:
Assertion (A): pH = 7 signifies pure water.
- This statement is true. Pure water at 25°C has a neutral pH of 7, which is a result of the equal concentrations of hydrogen ions [H+][H^+][H+] and hydroxide ions [OH−][OH^-][OH−].
Reason (R): At this pH, [H+] = [OH-] = 10^-7.
- This statement is also true. In pure water at 25°C, the concentration of hydrogen ions [H+][H^+][H+] and hydroxide ions [OH−][OH^-][OH−] are both 10−710^{-7}10−7 M, leading to a pH of 7.
Conclusion:
Both the assertion and the reason are true, and the reason correctly explains the assertion.
Therefore, the correct answer is:
4. Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
Free Test
FREE
| Start Free Test |
Community Answer
Assertion : pH = 7 signifies pure water.Reason : At this pH, [H+] = [O...
Assertion (A): pH = 7 signifies pure water.
Reason (R): At this pH, [H+] = [OH-]= 10-7.
Explanation:
The pH scale is a measure of the acidity or alkalinity of a solution. It is based on the concentration of hydrogen ions (H+) in the solution. The pH scale ranges from 0 to 14, with pH 7 considered neutral. A pH value below 7 indicates acidity, while a pH value above 7 indicates alkalinity.
In the case of pure water, the concentration of hydrogen ions (H+) is equal to the concentration of hydroxide ions (OH-). This is because water can undergo a self-ionization reaction, where it can break down into hydrogen ions and hydroxide ions:
H2O ⇌ H+ + OH-
In pure water, the concentration of H+ ions is equal to the concentration of OH- ions. This equilibrium is represented as [H+] = [OH-]. At room temperature, the concentration of H+ ions and OH- ions in pure water is approximately 10-7 moles per liter.
Therefore, at pH 7, the concentration of H+ ions in the solution is 10-7 moles per liter, which is equal to the concentration of OH- ions. This is why pH 7 is considered neutral.
However, it is important to note that the reason given does not fully explain why pH 7 signifies pure water. While the equality of [H+] = [OH-] at pH 7 is a characteristic of pure water, it does not provide a complete understanding of why pure water has a pH of 7. Other factors, such as the self-ionization of water, need to be considered.
Therefore, although both the assertion and reason are true, the reason is not the correct explanation of the assertion. Hence, the correct answer is option 'B' - Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
Reason (R): At this pH, [H+] = [OH-]= 10-7.
Explanation:
The pH scale is a measure of the acidity or alkalinity of a solution. It is based on the concentration of hydrogen ions (H+) in the solution. The pH scale ranges from 0 to 14, with pH 7 considered neutral. A pH value below 7 indicates acidity, while a pH value above 7 indicates alkalinity.
In the case of pure water, the concentration of hydrogen ions (H+) is equal to the concentration of hydroxide ions (OH-). This is because water can undergo a self-ionization reaction, where it can break down into hydrogen ions and hydroxide ions:
H2O ⇌ H+ + OH-
In pure water, the concentration of H+ ions is equal to the concentration of OH- ions. This equilibrium is represented as [H+] = [OH-]. At room temperature, the concentration of H+ ions and OH- ions in pure water is approximately 10-7 moles per liter.
Therefore, at pH 7, the concentration of H+ ions in the solution is 10-7 moles per liter, which is equal to the concentration of OH- ions. This is why pH 7 is considered neutral.
However, it is important to note that the reason given does not fully explain why pH 7 signifies pure water. While the equality of [H+] = [OH-] at pH 7 is a characteristic of pure water, it does not provide a complete understanding of why pure water has a pH of 7. Other factors, such as the self-ionization of water, need to be considered.
Therefore, although both the assertion and reason are true, the reason is not the correct explanation of the assertion. Hence, the correct answer is option 'B' - Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
|
Explore Courses for Class 10 exam
|
|
Similar Class 10 Doubts
Top Courses for Class 10View all
Question Description
Assertion : pH = 7 signifies pure water.Reason : At this pH, [H+] = [OH-]= 10-7.a)Assertion (A) is false but reason (R) is true.b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).c)Assertion (A) is true but reason (R) is false.d)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).e)Both Assertion and Reason are false.Correct answer is option 'D'. Can you explain this answer? for Class 10 2025 is part of Class 10 preparation. The Question and answers have been prepared according to the Class 10 exam syllabus. Information about Assertion : pH = 7 signifies pure water.Reason : At this pH, [H+] = [OH-]= 10-7.a)Assertion (A) is false but reason (R) is true.b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).c)Assertion (A) is true but reason (R) is false.d)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).e)Both Assertion and Reason are false.Correct answer is option 'D'. Can you explain this answer? covers all topics & solutions for Class 10 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Assertion : pH = 7 signifies pure water.Reason : At this pH, [H+] = [OH-]= 10-7.a)Assertion (A) is false but reason (R) is true.b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).c)Assertion (A) is true but reason (R) is false.d)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).e)Both Assertion and Reason are false.Correct answer is option 'D'. Can you explain this answer?.
Assertion : pH = 7 signifies pure water.Reason : At this pH, [H+] = [OH-]= 10-7.a)Assertion (A) is false but reason (R) is true.b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).c)Assertion (A) is true but reason (R) is false.d)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).e)Both Assertion and Reason are false.Correct answer is option 'D'. Can you explain this answer? for Class 10 2025 is part of Class 10 preparation. The Question and answers have been prepared according to the Class 10 exam syllabus. Information about Assertion : pH = 7 signifies pure water.Reason : At this pH, [H+] = [OH-]= 10-7.a)Assertion (A) is false but reason (R) is true.b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).c)Assertion (A) is true but reason (R) is false.d)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).e)Both Assertion and Reason are false.Correct answer is option 'D'. Can you explain this answer? covers all topics & solutions for Class 10 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Assertion : pH = 7 signifies pure water.Reason : At this pH, [H+] = [OH-]= 10-7.a)Assertion (A) is false but reason (R) is true.b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).c)Assertion (A) is true but reason (R) is false.d)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).e)Both Assertion and Reason are false.Correct answer is option 'D'. Can you explain this answer?.
Solutions for Assertion : pH = 7 signifies pure water.Reason : At this pH, [H+] = [OH-]= 10-7.a)Assertion (A) is false but reason (R) is true.b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).c)Assertion (A) is true but reason (R) is false.d)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).e)Both Assertion and Reason are false.Correct answer is option 'D'. Can you explain this answer? in English & in Hindi are available as part of our courses for Class 10.
Download more important topics, notes, lectures and mock test series for Class 10 Exam by signing up for free.
Here you can find the meaning of Assertion : pH = 7 signifies pure water.Reason : At this pH, [H+] = [OH-]= 10-7.a)Assertion (A) is false but reason (R) is true.b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).c)Assertion (A) is true but reason (R) is false.d)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).e)Both Assertion and Reason are false.Correct answer is option 'D'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of
Assertion : pH = 7 signifies pure water.Reason : At this pH, [H+] = [OH-]= 10-7.a)Assertion (A) is false but reason (R) is true.b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).c)Assertion (A) is true but reason (R) is false.d)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).e)Both Assertion and Reason are false.Correct answer is option 'D'. Can you explain this answer?, a detailed solution for Assertion : pH = 7 signifies pure water.Reason : At this pH, [H+] = [OH-]= 10-7.a)Assertion (A) is false but reason (R) is true.b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).c)Assertion (A) is true but reason (R) is false.d)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).e)Both Assertion and Reason are false.Correct answer is option 'D'. Can you explain this answer? has been provided alongside types of Assertion : pH = 7 signifies pure water.Reason : At this pH, [H+] = [OH-]= 10-7.a)Assertion (A) is false but reason (R) is true.b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).c)Assertion (A) is true but reason (R) is false.d)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).e)Both Assertion and Reason are false.Correct answer is option 'D'. Can you explain this answer? theory, EduRev gives you an
ample number of questions to practice Assertion : pH = 7 signifies pure water.Reason : At this pH, [H+] = [OH-]= 10-7.a)Assertion (A) is false but reason (R) is true.b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).c)Assertion (A) is true but reason (R) is false.d)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).e)Both Assertion and Reason are false.Correct answer is option 'D'. Can you explain this answer? tests, examples and also practice Class 10 tests.
|
|
Explore Courses for Class 10 exam
|
|
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
|
© EduRev
|
Education Revolution
|
|
Signup to see your scores
go up within 7 days!
Access 1000+ FREE Docs, Videos and Tests
Takes less than 10 seconds to signup