Sony HX50V has a
20.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor . On the other hand, Canon A2100 IS has a
12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor .
Sony HX50V's sensor provides 8MP more than Canon A2100 IS's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the HX50V and A2100 IS sensor size comparison.
Sony HX50V and Canon A2100 IS have the same sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture. On the other hand, since Canon A2100 IS has 26% larger pixel area (2.34µm2 vs 1.85µm2) compared to Sony HX50V, it has larger pixel area to collect light hence potential to have less noise in low light / High ISO images.