All Courses
Explore Courses UPSC Exam UPSC Test Series Free Notes EduRev Infinity Get the App Login Join for Free
Sign in Open App
UPSC Exam  >  UPSC Questions  >  How much water must be added to a 100 cc of 8... Start Learning for Free
How much water must be added to a 100 cc of 80% solution of boric acid to reduce it to a 50% solution?
  • a)
    20 cc
  • b)
    40 cc
  • c)
    80 cc
  • d)
    60 cc
Correct answer is option 'D'. Can you explain this answer?
Clear all your UPSC doubts with EduRev
Verified Answer
How much water must be added to a 100 cc of 80% solution of boric acid...
Quantity of boric acid in 100 cc solution = 80% of 100 cc = 80 cc
Quantity of water in 100 cc solution = 100 cc - 80 cc = 20 cc
Let x cc of water be added to get the concentration of 50%.
So, (80)/(100 + x) = 50/100
or (80)/(100 + x) = 1/2
or 80 × 2 = (100 + x)
or x = 160 - 100 = 60 cc
Thus, 60 cc of water must be added.
Hence, option (d) is correct.
Alternate method:
Concentration of boric acid in 100 cc solution = 80% of 100 cc = 80 cc
Quantity of water in 100 cc solution = 100 cc - 80 cc = 20 cc
Here we are adding water.
So, amount of boric acid is fixed.
When water is added to the solution, boric acid reduces to 50% of the solution.
Thus, 50% of the solution contains 80 cc.
So, 100% of the solution contains 160 cc.
Amount of water to be added in the solution = 160 cc - 100 cc = 60 cc
Hence, option (d) is correct.
View all questions of this test
Most Upvoted Answer
How much water must be added to a 100 cc of 80% solution of boric acid...
Given:
- Initial volume of 80% boric acid solution = 100 cc
- Desired final concentration = 50%

Calculations:
- Let x be the amount of water to be added to reduce the concentration.
- Initial amount of boric acid in the solution = 80% of 100 cc = 80 cc
- Final volume of the solution after adding water = 100 cc + x
- Final amount of boric acid in the solution after adding water = 50% of (100 + x) cc

Equation:
- Amount of boric acid before = Amount of boric acid after
- 80 cc = 50% of (100 + x)
- 80 = 0.5(100 + x)
- 80 = 50 + 0.5x
- 0.5x = 30
- x = 60 cc
Therefore, 60 cc of water must be added to 100 cc of 80% boric acid solution to reduce it to a 50% solution. Hence, the correct answer is option D.
Explore Courses for UPSC exam

Similar UPSC Doubts

Passage 2It is essential that we mitigate the emissions of greenhouse gases .and thus avoid some of the worst impacts of climate change that would take place in coming years and decades. Mitigation would require a major shift in the way we produce and consume energy. A shift away from overwhelming dependence on fossil fuels is now long overdue, but unfortunately, technological development has been slow arid inadequate largely because government policies have not promoted investments in research and development, myopically as a result of relatively low prices of oil. It is now, therefore, imperative for a country like India treating the opportunity of harnessing renewable energy on a large scale as a national imperative. This country is extremely well endowed with solar, wind and biomass sources of energy. Where we have lagged, unfortunately, is in our ability to develop and to create technological solutions for harnessing these resources.One particular trajectory for carrying out stringent mitigation of greenhouse gas emissions assessed by the Inter-governmental Panel on Climate Change (IPCC) clearly shows the need for ensuring that global emissions of greenhouse gases peak no later than 2015 and reduce rapidly thereafter. The cost associated with such a trajectory is truly modest and would amount, in the estimation of IPCC, to not more than 3 percent of the global GDP in 2030. In other words, the level of prosperity that the world would have reached without mitigation would at worst be postponed by a few months or a year at the most. This is clearly not a very high price to pay for protecting hundreds of millions of people from the worst risks associated with climate change. Any such effort, however, would require lifestyles to change appropriately also. Mitigation of greenhouse gas emissions is not a mere technological fix, and clearly requires changes in lifestyles and transformation of a countrys economic structure, whereby effective reduction in emissions is brought about, such as through the consumption of much lower quantities of animal protein. The Food and Agriculture Organization (FAO) has determined that the emissions from the livestock sector amount to 18 percent of the total. The reduction of emissions from this source is entirely in the hands of human beings, who have never questioned the impacts that their dietary habits of consuming more and more animal protein are bringing about. Mitigation overall has huge co-benefits, such as lower air pollution and health benefits, higher energy security and greater employment.Q.According to the passage, how does the mitigation of greenhouse gases help us?1. Reduces expenditure on public health2. Reduces dependence on livestock3. Reduces energy requirements4. Reduces rate of global climate change

Top Courses for UPSCView all

Top Courses for UPSC

How much water must be added to a 100 cc of 80% solution of boric acid to reduce it to a 50% solution?a)20 ccb)40 ccc)80 ccd)60 ccCorrect answer is option 'D'. Can you explain this answer?
Question Description
How much water must be added to a 100 cc of 80% solution of boric acid to reduce it to a 50% solution?a)20 ccb)40 ccc)80 ccd)60 ccCorrect answer is option 'D'. Can you explain this answer? for UPSC 2025 is part of UPSC preparation. The Question and answers have been prepared according to the UPSC exam syllabus. Information about How much water must be added to a 100 cc of 80% solution of boric acid to reduce it to a 50% solution?a)20 ccb)40 ccc)80 ccd)60 ccCorrect answer is option 'D'. Can you explain this answer? covers all topics & solutions for UPSC 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for How much water must be added to a 100 cc of 80% solution of boric acid to reduce it to a 50% solution?a)20 ccb)40 ccc)80 ccd)60 ccCorrect answer is option 'D'. Can you explain this answer?.
Solutions for How much water must be added to a 100 cc of 80% solution of boric acid to reduce it to a 50% solution?a)20 ccb)40 ccc)80 ccd)60 ccCorrect answer is option 'D'. Can you explain this answer? in English & in Hindi are available as part of our courses for UPSC. Download more important topics, notes, lectures and mock test series for UPSC Exam by signing up for free.
Here you can find the meaning of How much water must be added to a 100 cc of 80% solution of boric acid to reduce it to a 50% solution?a)20 ccb)40 ccc)80 ccd)60 ccCorrect answer is option 'D'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of How much water must be added to a 100 cc of 80% solution of boric acid to reduce it to a 50% solution?a)20 ccb)40 ccc)80 ccd)60 ccCorrect answer is option 'D'. Can you explain this answer?, a detailed solution for How much water must be added to a 100 cc of 80% solution of boric acid to reduce it to a 50% solution?a)20 ccb)40 ccc)80 ccd)60 ccCorrect answer is option 'D'. Can you explain this answer? has been provided alongside types of How much water must be added to a 100 cc of 80% solution of boric acid to reduce it to a 50% solution?a)20 ccb)40 ccc)80 ccd)60 ccCorrect answer is option 'D'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice How much water must be added to a 100 cc of 80% solution of boric acid to reduce it to a 50% solution?a)20 ccb)40 ccc)80 ccd)60 ccCorrect answer is option 'D'. Can you explain this answer? tests, examples and also practice UPSC tests.
Explore Courses for UPSC exam

Top Courses for UPSC

Explore Courses
SaveJoin the Discussion on the App for FREE
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev
Get App
© 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