MEDIUM
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The purity of H2O2 in a given sample is 85%. Calculate the weight of impure sample of H2O2 that requires 10 mL M5 KMnO4 solution for titration in acidic medium.

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Important Questions on Redox Reactions

HARD
0.4 g mixture of NaOH,Na2CO3 and some inert impurities was first titrated with N10HCl using phenolphthalein as an indicator, 17.5 mL of HCl was required at the end point. After this methyl orange was added and titrated. 1.5 mL of same HCl was required for the next end point. The weight percentage of Na2CO3 in the mixture is (Rounded-off to the nearest integer)
HARD
Identify the correct statements from the following.
i.In CoClNH352+, the Lewis acid is Co3+
ii. An example for heteroleptic complex is CoNH363+
iii. The hybridisation of Mn in MnBr42- is dsp2
iv. In Ni(CO)4, the metal-carbon bond possesses σ and π character.
HARD

In a titration experiment, 10 mL of an FeCl2 solution consumed 25 mL of a standard K2Cr2O7 solution to reach the equivalent point. The standard K2Cr2O7 solution is prepared by dissolving 1.225 g of K2Cr2O7 in 250 mL water. The concentration of the FeCl2 solution is closest to

[Given : molecular weight of K2Cr2O7=294 g mol-1]

MEDIUM
Given below are two statements:
Statement I : In the titration between strong acid and weak base methyl orange is suitable as an indicator.
Statement II : For titration of acetic acid with $\mathrm{NaOH}$ phenolphthalein is not a suitable indicator.
In the light of the above statements, choose the most appropriate answer from the options given below:
HARD
To measure the quantity of MnCl2 dissolved in an aqueous solution, it was completely converted to KMnO4 using the reaction,

MnCl2+K2S2O8+H2OKMnO4+H2SO4+HCl (equation not balanced). Few drops of concentrated HCl were added to this solution and gently warmed. Further, oxalic acid 225 mg) was added in portions till the colour of the permanganate ion disappeared. What is the quantity of MnCl2 (in mg) present in the initial solution? (Atomic weights in g mol-1: Mn=55, Cl=35.5)
EASY

In the given chemical reaction, colors of theFe2+ and Fe3+ ions, are respectively :

5Fe2++MnO4-+8H+Mn2++4H2O+5Fe3+

MEDIUM
2KMnO4+3H2SO4+5H2O2K2SO4+2MnSO4+8H2O+5O2
Find the nonnality of H2O2 solution, if 20 mL of it is required to react completely with 16 mL of 0.02MKMnO4 solution. ( Molar mass of KMnO4=158 g mol-1)
MEDIUM
A mixture of 2.3 g formic acid and 4.5 g oxalic acid is treated with concentrated H2SO4. The evolved gaseous mixture is passed through KOH pellets. What will be the weight in grams of the remaining product at STP?
EASY
While titration dilute HCl solution with aqueous NaOH, which of the following will not be required ?
MEDIUM
In the titration of I2 aq by S2O32- aq using the starch indicator, the end point is indicated by:
HARD
Number of moles of dichromate needed to oxidise one mole of Sn2+ is
HARD
In a complexometric titration of metal ion with ligand M (Metal ion)+L(Ligand)C (Complex) end point is estimated spectrophotometrically (through light absorption). If 'M' and 'C' do not absorb light and only 'L' absorbs then the titration plot between absorbed light (A) versus volume of ligand 'L' (V) would look like:
MEDIUM
Excess of acidic solution of KI to mixed with 25 mL H2O2. Liberated I2 requires 20 mL of 0.3 N Na2S2O3 solution. The volume strength of H2O2 is
MEDIUM
In Tollen's test for aldehyde, the overall number of electron(s) transferred to the Tollen's reagent formula AgNH32+ per aldehyde group to form silver mirror is ___.(Round off to the Nearest integer)
HARD

For kinetic study of the reaction of iodide ion with H2O2 at room temperature :

(A) Always use freshly prepared starch solution.

(B) Always keep the concentration of sodium thiosulphate solution less than that of KI solution.

(C) Record the time immediately after the appearance of blue colour.

(D) Record the time immediately before the appearance of blue colour.

(E) Always keep the concentration of sodium thiosulphate solution more than that of KI solution.

Choose the correct answer from the options given below

MEDIUM
0.01MKMnO4 solution was added to 20.0 mL of 0.05M Mohr 's salt solution through a burette. The initial reading of 50 mL burette is zero. The volume of KMnO4 solution left in the burette after the end point is....... mL. (nearest integer)
HARD
A 2.0 g sample containing MnO2 is treated with HCl liberating Cl2. The Cl2 gas is passed into a solution of KI and 60.0mL of 0.1MNaS2O3 is required to titrate the liberated iodine. The percentage of MnO2 in the sample is____. Nearest integer)
[Atomic masses (in u) Mn=55;Cl=35.5:O=16,I=127,Na=23,K=39,S=32]
HARD
The volume of 0.1MKMnO4 solution required to completely react with a solution obtained by dissolving 0.63 g of oxalic acid (molar mass 126gmol-1) in 50 mL distilled water in acidic medium in mL is
MEDIUM
An alkali is titrated against acid with methyl orange as an indicator, which of the following is a correct combination?
MEDIUM
50mL of 0.5M oxalic acid is needed to neutralize 25mL of sodium hydroxide solution. What is the amount of NaOH in 50mL of the given sodium hydroxide solution?