The water acidity in a pool is considered normal when the average pH of the three measurements is between 8.2 and 8.5. if the first two pH reading are 8,48 and 8,35, find the range of pH of the third reading that will result in acidity level being normal.

The water acidity in a pool is considered normal when the average pH reading of three daily measurements is between 7.2 and 7.8. If the first two pH readings are 7.48 and 7.85, find the range of pH value for the third reading that will result in the acidity level being normal.

Why does rain water normally have a pH of about 5.6 ? When does it become acid rain ?

The mean of 5 observation is 4.4 and their variance is 8.24 . If three of the observations are 1,2 and 6, find the other two observations

A parallel combination of three resistors takes a current of 5A from a 20V supply. If the two resistors are of 10 ohm and 8 ohm, find the value of third resistor.

A beam of ligth consisting of two wavelength 4,800 overset@A and 6,000 overset@A is used to obtain interfernce fringes in a double slit experiment.The distnce between the slits is 1.8 mm and the distance of screen from the plane of slits is 1.2 m Find the distance of the third bright frings on the screen from the central maximum for the wavelength 6,000 overset @A .

Three normals are drawn from the point (14,7) to the curve y^2-16x-8y=0 . Find the coordinates of the feet of the normals.

10 mL of H_(2)A (weak diprtic acid) solutio is titrated against 0.1M NaOH. pH of the solution is plotted against volume of strong base added and following obserbation is made Ip pH of the solution at first equivalence point is pH_(1) and at secnd equibalence point is pH_(2^.) Calculate the value of (pH_(2)-pH_(1)) at 25^(@)C Given for H_(2)A,pK_(a_1) =4.6 and pK_(a_2) =8, log 25=1.4