Question

Calculate the\[pH\]of orange juice in which hydronium ion conc. \[\left( {{H_{3}}{O^ + }} \right)\;is{\text{ }}2\; \times \;{10^{ - 8\;}}mol/l\;.\]

Answer 1

Hint:To calculate the \[pH\] of a orange juice , we have to used the formula: \[pH\]=\[ - lo{g_{10}}\left[ {{H_3}{O^ + }} \right]\]. As per equation, the \[pH\] of a solution is the negative of base \[10\]logarithm of hydronium ion concentration in a solution. The concentration of hydronium ions in an aqueous solution can provide information about the acidic, basic, or neutral nature of a solution. At room temperature, the pH of neutral water is equal to \[7\].

Complete step by step answer:
\[pH\] stands for potential of hydrogen and \[pH\] scale is a logarithmic scale that is used to measure the acidity or the basicity of a substance. The range of the scale varies from \[0{\text{ }}to{\text{ }}14\]. Solutions having a value of \[pH\] ranging\[\;0{\text{ }}to{\text{ }}7\]on \[pH\] scale are known as acidic and for the value of \[pH\] ranging \[7{\text{ }}to{\text{ }}14\]on \[pH\] scale are called basic solutions and the Solutions having the value of pH equal to \[7\] on \[pH\] scale are termed as neutral solutions.
When we determine the \[pH\] value of orange juice, we need to know the concentration of hydronium ions in moles per liter (molarity) of the solution.
To calculate the \[pH\] of a solution, use the equation \[pH\]= \[ - lo{g_{10}}\left[ {{H_3}{O^ + }} \right]\]
Given,
Concentration of Hydronium Ion \[\left( {{H_3}{O^ + }} \right)\]\[ = 2 \times {10^{ - 8}}moles/l\]
\[\left[ {{H_3}{O^ + }} \right]\] \[ = 2 \times {10^{ - 8}}\]
\[pH\]=\[ - lo{g_{10}}\left[ {{H_3}{O^ + }} \right]\]
\[pH = - lo{g_{10}}\left[ {2 \times {{10}^{ - 8}}} \right]\]
By solving the log
\[\therefore \] we know that, \[{\log _{10}}10 = 1\] and \[log2 = 0.3010\]
\[pH = - \left[ {lo{g_{10}}(2) + {{\log }_{10}}({{10}^{ - 8}})} \right]\]
\[pH = - \left[ {0.3010 - 8} \right]\]
\[pH = 8 - 0.3010\]
\[pH = 7.6990\]
Note: \[pH\;\] measurement is used in a wide variety of applications: agriculture, wastewater treatment, industrial processes, environmental monitoring, and in research and development. In our real life \[pH\;\] is important because substances such as our stomach acids tend to be at certain \[pH\] in order to work properly and it must be at certain levels in order for living organisms to survive.