A buffer is prepared from 0.040 mol NH₄⁺ and 0.060 mol NH₃ in a total volume of 200 mL. A student adds 15.0 mL of 0.50 M HCl to the buffer. Without calculating the exact pH, determine whether the final pH will be higher, lower, or approximately unchanged compared with the initial pH, and briefly indicate whether either buffer component is completely consumed.