प्रदूषित वातावरण में देखा जाने वाला शास्त्रीय अपचायक धूम-कोहरा (reducing smog) मुख्य रूप से किसका मिश्रण होता है?

Temporary hardness in water is also known as:

Which of the following have been used as alternatives to chlorofluorocarbons (CFCs) as refrigerants? A. Hydrofluorocarbons B. Perfluorocarbons C. Hydrochlorofluorocarbons D. Halons

Ocean acidification occurs due to the reaction of atmospheric carbon dioxide with sea water to produce which of the following?