In a test on the vaporization of H$2$O into air in a wetted$-$wall column, the following data were obtained: tube diameter $=1\mathrm{.}46$ cm; The operation was countercurrent with gas entering at the bottom of the vertical tower and the acid passing down in a thin ilm on the vertical, cylindrical inner wall. The change in acid strength was negligible, and the vapor pressure of ammonia over the liquid is negligible because of the use of a strong acid for absorption$.$ Calculate the mass$-$transfer coeficient, kp$,$ from the data.