Crack the Problem

1. x
2. y
3. z
4. n

Submission Closed

Cracked by:

1. Aditya Gopi, 12'th, C.M.R N.P.S, Bangalore.

2. Ajay N. Nandoriya, 12'th, School of Science, Rajkot.

3. Udit Khanna, 12'th, St. Anselm’s Pink City School, Jaipur.

4. Ankul Garg, 12'th, Bal Bharti Public School, Rohini, Delhi.

Udit's Solution:

Let the no. of millimoles of the salt in 30 ml soln = a

Then, the no. of meqts of H⁺ = ay (let meqts = milliequivalents)

Since meqts of H⁺ = meqts of OH^- in NaOH

Therefore, ay = 27 * 0.12 = 3.24 ………….(i)

No. of meqts of C₂O₄^2- = 2az

Again since meqts of C₂O₄^2- = meqts of MnO₄^- in KMnO₄

Therefore, 2az = 36 * 0.12 = 4.32 ………….(ii)

Since salt must be electrically neutral,

Therefore, x + y = 2z ……………………(iii)

From (i), (ii) and (iii) , we get ,

x : y : z = 1 : 3 : 2

Since, x, y and z are the simplest ratio’s, therefore,

x = 1

y = 3

z = 2

From (i), a * 3 = 3.24

=> a = 1.08 …………………..(iv)

Molecular wt. of the salt = (39 * 1) + (1 * 3) + (88 * 2) + (18 * n)

= 218 + 18n

wt. of salt in 1 Lt. soln = 9.15 gm

=> wt. of salt in 30 ml soln = 9.15 * 30 milligram = 274.5 mgm

=> moles of salt in 30 ml soln = mmoles

=> a =

=> n = 2

Hence, the answers are,

x = 1

y = 3

z = 2

n = 2

And the salt is : KH₃(C₂O₄)₂.2H₂O

Ankul's Solution is attached (.pdf).