HomeEngineeringMaximum allowable concentration of CO₂ in air for safe working is __________ ppm (parts per million). 5901. Maximum allowable concentration of CO₂ in air for safe working is __________ ppm (parts per million).By Admin / September 7, 2025 50 1000 2000 5000 ✅ The correct answer is option D.
1. A fire tube boiler is limited to a maximum steam pressure of about __________ kg/cm². Leave a Comment / Basic Chemical Engineering MCQs, Chemical Engineering, Engineering / By Admin
2. Transformer cores are normally made from Leave a Comment / Basic Chemical Engineering MCQs, Chemical Engineering, Engineering / By Admin