My question is on number three I don't think the answers I have so far are correct.
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a) is correct. For b) you have to use the result from a) to calculate the moles of iron according the chemical reaction, which you should develop first.
From that result you can solve c) to get the mass of iron by using molar mass of iron and at the end you can get the ratio from the given sample d).

Quote from: Harini on October 26, 2022, 09:27:42 PM
My question is on number three I don't think the answers I have so far are correct.

Most important part missing is the balanced redox reaction. You can do calculations only on balanced reactions.
MnO₄^- + 5Fe ²⁺ -------->  Mn ²⁺   +5 Fe ³⁺
a) moles of MnO₄^- = M * V (L)
b) Moles of Fe²⁺ reacted with Moles of MnO₄^- is 5 times of moles of MnO₄^-
c) Once you know moles of Fe³⁺ , you can convert it to grams of Fe in the reaction..
d)Now you know grams of Fe and grams of sample ,you can calculate % mass of Fe in the sample.
Try it now.Let me know in case you have any doubt left.

Be honest. This equation is also not balanced.
MnO4- + 5Fe 2+ -------->  Mn 2+   +5 Fe 3+
Either the number of atoms left and right and also the charges left +9 right + 17.

Quote from: chenbeier on November 09, 2022, 03:47:02 AM
Be honest. This equation is also not balanced.
MnO4- + 5Fe 2+ -------->  Mn 2+   +5 Fe 3+
Either the number of atoms left and right and also the charges left +9 right + 17.

I have shown the balancing of only atoms undergoing oxidation and reduction. So it can be used in our questions.
In many questions we just use species undergoing change in oxidation number. So it is just showing partial balanced equation which can be used in our question.