Question : State whether the following are true or false.
SO2 gas changes the colour of a KMnO4(aq) solution
They have taken this as false and given the following equation:
SO2+H2O+2KMnO4-->K2SO4+MnSO4+H2SO4 (not balanced)
But why they have taken this as false when Mn2+ created here is colourless (Does K2SO4 has a colour?)
When the medium is acidic,the colour of the solution does change from purple(MnO4^- is purple and SO2 is colourless) to colourless (Mn^2+) right?
And they haven't given whether the medium is acidic/basic,too.
[From what I've learned this reaction takes place in acidic medium(MnO4^- -->Mn^2+) ]
And I've learned that in basic medium they react as follows;
MnO4^- + SO2+4OH^- -->MnO2+SO4^2- + H2O (not balanced)
And in this case the colour of the solution should change from purple(MnO4^-) to brown/black (MnO2)
So,to my knowledge, in these both cases,the colour of the solution does change.
So I don't understand why they've taken the above statement as false.
I don't understand it either. I don't see anything wrong with your reasoning.
Hmm..Thank you very much
I agree.
Based on the information you have provided, it seems that there might be some confusion in the question and the given answer. Let me break it down for you:
1. The original statement is: "SO2 gas changes the color of a KMnO4(aq) solution." To determine whether this statement is true or false, we need to examine the reaction between SO2 and KMnO4.
2. In an acidic medium, the balanced equation for the reaction between SO2 and KMnO4 would be: SO2 + H2O + 2KMnO4 -> K2SO4 + MnSO4 + H2SO4. Here, the Mn2+ formed is indeed colorless, but the K2SO4 formed does not have any significant color.
3. However, it is important to note that the color change in the KMnO4 solution is primarily due to the reduction of the MnO4- ion to Mn2+. In this case, the purple color of MnO4- changes to colorless Mn2+. Therefore, in an acidic medium, the statement "SO2 gas changes the color of a KMnO4(aq) solution" would be considered true since the color of the solution does change.
4. You also mentioned that in a basic medium, the reaction is different, and it forms MnO2, which is brown/black in color. This is also correct, but the given equation refers to the reaction in an acidic medium.
In summary, based on the information you provided, the answer "false" for the given statement seems inconsistent with the actual behavior of the KMnO4 solution in an acidic medium. The color does change when SO2 reacts with KMnO4. However, it is important to consider the specific reaction conditions (acidic or basic medium) as they can affect the outcome.