The textbook 6,300 Problemas de Química Básica (also known in earlier editions as "3,800 Problemas de Química Básica") by Rolando Álvarez

The search for the "6,300 problems" version suggests it is likely an expanded edition or a common misremembering of Rolando Alva Alvarez's famous academic work, typically cited as 3,800 Problemas de Química Básica

(often also found as the 3800 or 6700 problem editions) can be challenging as it is primarily a physical workbook used in academic settings in Bolivia and surrounding regions.