Average value of E = - 8.7 What is the beta (electromotive efficiency)? The answ

Question

Average value of E = - 8.7

What is the beta (electromotive efficiency)? The answer is 0.955 but how do get it?

What is dlog[Ca2+]? I got 0.061 but it is incorrect.

log[Ca2+] = (y-b)/m = (-8.7-54.504)/28.26 = -2.236

Standard solutions Measured electrode potential [Ca2+] 4.64x10-5 4.64x104 4.64x10-3 4.64x10-2 4.64x101 E (mV) 68.6 -40.0 9.8 17.0 44.2 Sy Sb Sm Sx 28.26 54.5042 1.15412 0.99584 0.36497 0.02789 -201 : ?" . -4 3.5 -3 2.5 2-1.5-1 0.5 Log[Ca2+ )logACa2+ E (in Volts,-constant+?(0.05916 dlog[Ca2+]=Ilog[Ca2+]| |(y@dy)'t2 ) +(?2 = y-b

Explanation / Answer

Answer-

part-1

It is Ion-Selective Electrode Determination of Calcium ion .

The amount of a specific ion contained in an aqueous solution can be determined by direct potentiometric measurement of the voltage of a galvanic cell such as shown below.

reference electrode /analyte solution ion/ selective electrode- ( Side convention)

From derivation

E(in Volts)=Constant -( 2.303RT/nF) log (a ion outer/aion inner)-----------(1)  

after putting value of referance activity in eqn- 1 it becomes (2) it varies slightly depending on selected ions .

E(in Volts)=Constant +( 0.05916/n) log (aCa2+) ------------(2)

comparing eqn (1) with given in question

0.0591/2 = ? x (0.0591/2 )

right hand side part can be calculated simply by equation 1

So it is always near to unity in present case it is 0.955 .

it has nothing with equation Y=mX+C in present case . It can be calculated by putting activity of refence ion in eqn-(1) with n,R,F values with their appropriate values.

part-2

for dlog[Ca2+]

choose any integral value for the simplicity it is -2 which corresponds to 0 volt electrode potential.

putting the values from table in the equation,

dlog[Ca2+] =(-2)[ ((dy)2+Sb2)/(y-b))2 +(Sm/m)2]1/2

  =-2 x [ ((60)2+(0.99584)2)/(0-54.50))2 +(0.36497/28.26)2 ]1/2

=-132

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.