Is the Canon EF 24-70mm f/2.8L II USM Lens sharp? This page visually answers that question. Shown above are 100% crops from a lab-captured 50mm f/11.0 test image. Observe the contrast and resolution of these results.
Is the Canon EF 24-70mm f/2.8L II USM Lens set to 50mm f/11.0 sharper than the Tamron 35-150mm f/2-2.8 Di III VXD Lens set to 35mm f/2.8? The image quality comparison above also answers that question. Switch between the results to see the sharpness differences between these lenses.