16Permanent hardness is removed by:ALime–soda process or ion exchangeBSedimentation onlyCScreeningDBoilingView AnswerDiscussWorkspaceReportSaveEasy
17The acceptable pH range of drinking water (BIS) is:A9–11B4–5C1–3D6.5–8.5View AnswerDiscussWorkspaceReportSaveEasy
18A town of 50,000 people with demand 150 L per person per day needs a daily supply of:A750,000 litresB7.5 million litresC3,333 litresD75 million litresView AnswerDiscussWorkspaceReportSaveMedium