Consider an oil-to-oil double-pipe heat exchanger whose flow arrangement is not known. The temperature measurements indicate tha
t the cold oil enters at 15°C and leaves at 55°C, while the hot oil enters at 80°C and leaves at 40°C. Do you think this is a parallel-flow or counter-flow heat exchanger? Why? Assuming the mass flow rates of both fluids to be identical, determine the effectiveness of this heat exchanger.
1 answer:
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<u>Explanation:</u>
pH is the negative logarithm of hydronium ion concentration present in a solution.
- If the solution has high hydrogen ion concentration, then the pH will be low and the solution will be acidic. The pH range of acidic solution is 0 to 6.9
- If the solution has low hydrogen ion concentration, then the pH will be high and the solution will be basic. The pH range of basic solution is 7.1 to 14
- The solution having pH equal to 7 is termed as neutral solution.
To calculate the pH of the solution, we use equation:
......(1)
To calculate the pOH of the solution, we use the equation:
pH + pOH = 14 ........(2)
- <u>For 1:</u>
We are given:
pH = 5.54
Putting values in equation 1, we get:
Now, putting values in equation 2, we get:
14 = 5.54 + pOH
pOH = 8.46
The solution is acidic in nature.
- <u>For 2:</u>
We are given:
pOH = 9.7
Putting values in equation 2, we get:
14 = 9.7 + pH
pH = 4.3
Now, putting values in equation 1, we get:
The solution is acidic in nature.
- <u>For 3:</u>
We are given:
pH = 7.0
Putting values in equation 1, we get:
Now, putting values in equation 2, we get:
14 = 7.0 + pOH
pOH = 7.0
The solution is neither acidic nor basic in nature.
- <u>For 4:</u>
We are given:
pH = 12.9
Putting values in equation 1, we get:
Now, putting values in equation 2, we get:
14 = 12.9 + pOH
pOH = 1.1
The solution is basic in nature.
- <u>For 5:</u>
We are given:
pOH = 1.2
Putting values in equation 2, we get:
14 = 1.2 + pH
pH = 12.8
Now, putting values in equation 1, we get:
The solution is basic in nature.
- <u>For 6:</u>
We are given:
Putting values in equation 1, we get:
Now, putting values in equation 2, we get:
14 = 5 + pOH
pOH = 9
The solution is acidic in nature.