For the titration of hcl versus NaOh, suggest a better indicator than methyl orange. Why is methyl orange not the ideal choice for this application?
The pH at the equivalence point of HCl vs NaOH titration is 7.0. MO is not a good indicator for this titration because it changes about 3.5. A better choice is phenolphthalein which changes about 9 or even methyl red which changes about 5.0.Bromothymol blue or phenol red are appropriate also.
A better indicator for the titration of HCl versus NaOH is phenolphthalein. Methyl orange is not the ideal choice for this application due to the following reasons:
1. pH range: Methyl orange changes color in the pH range of 3.1 to 4.4, which is not ideal for the HCl and NaOH titration. The equivalence point for this titration occurs around pH 7, where neither the acidic nor basic form of methyl orange shows a distinct color change.
2. Sensitivity: Methyl orange is less sensitive compared to phenolphthalein. Its color change is not as sharp, which can make it more difficult to pinpoint the exact point of neutralization during the titration.
On the other hand, phenolphthalein is a suitable choice for this titration because it changes from colorless to pink in the pH range of approximately 8.2 to 10.0, encompassing the pH of the equivalence point for this titration. The color change is distinct and makes it easier to determine the endpoint accurately.
To suggest a better indicator for the titration of HCl versus NaOH, we need to consider the pH range at which the titration takes place.
Methyl orange is commonly used as an indicator for acid-base titrations, but it may not be the ideal choice for the HCl versus NaOH titration. Methyl orange changes color at a pH range of approximately 3.1 to 4.4, with a distinct color change from red to yellow. However, in the HCl versus NaOH titration, the equivalence point occurs when the moles of acid and base are stoichiometrically balanced.
HCl is a strong acid, and NaOH is a strong base, meaning they completely ionize in water. The reaction between HCl and NaOH yields water and sodium chloride (NaCl). At the equivalence point, equal moles of HCl and NaOH react, resulting in a neutral solution with a pH of 7.
Methyl orange's color change occurs well before reaching the neutral pH range. Thus, it would not provide an accurate indication of the equivalence point in the HCl versus NaOH titration.
A more suitable indicator for this titration would be phenolphthalein. Phenolphthalein is commonly used for acid-base titrations with strong acids and strong bases. It changes color within the pH range of approximately 8.2 to 10.0. The color transition is from colorless to pink, making it well-suited for detecting the endpoint of the HCl versus NaOH titration, which occurs at a neutral pH of 7.