B, when choosing a measuring cylinder, try to choose the smallest measuring cylinder that can be measured at one time. Measure 5.26mL of hydrochloric acid with a 100mL measuring cylinder. The selection of measuring cylinder is unreasonable, so 10mL measuring cylinder is selected. And the precision of 10mL measuring cylinder is 0. 1mL, and the precision of 5.26mL measuring cylinder that does not meet 10mL is 0. 1mL, so it cannot be measured. So the option data is unreasonable.

C, because the number on the standard colorimetric card is only an integer, the pH value of the solution can not be accurately measured with a wide range pH test paper, so the experimental data is unreasonable.

D. Tray balance is used to roughly weigh the quality of drugs, and it can be accurate to 0. 1g, but it can't be accurate to 0.01g. 8.36g zinc particles can't be weighed by tray balance, so the selected experimental data is unreasonable.

So choose: a.