To find the concentration of calcium ions Ca2+ in the given solution, we can use the Nernst equation, which relates the electrode potential E to the concentration of ions in the solution:E = E0 + 2.303 * R * T / n * F * log10 C Where:E = electrode potential 0.0032 V E0 = standard electrode potential unknown R = gas constant 8.314 J/mol*K T = temperature assume 298 K, room temperature n = number of electrons transferred 2 for Ca2+ F = Faraday's constant 96485 C/mol C = concentration of calcium ions unknown The slope of the calibration curve is given as -28.4 mV per decade. This means that for every 10-fold increase in concentration, the electrode potential decreases by 28.4 mV. We can rewrite the Nernst equation in terms of the slope:Slope = 2.303 * R * T / n * F Now, we can solve for the concentration C using the given electrode potential E and slope:0.0032 V = E0 + -28.4 mV/decade * log10 C Since we don't know the standard electrode potential E0 , we cannot directly solve for the concentration C . However, we can use a calibration curve to find the concentration of calcium ions in the solution. To do this, you would need to have a set of known concentrations of calcium ions and their corresponding electrode potentials. Plot these points on a graph, and draw a line of best fit. The slope of this line should be -28.4 mV per decade. Then, find the point on the line that corresponds to an electrode potential of 0.0032 V, and read off the corresponding concentration of calcium ions.Without the calibration curve data, it is not possible to provide an exact concentration of calcium ions in the given solution.