Multiple choice

Which of the following statements is/are incorrect?

P. The central metal atom shows +4 oxidation state in potassium chromate and potassium dichromate. Q. Limonite and willemenite are ores of zinc. R. Zinc oxide is called as white lead with the formula (PbCO3)2•Pb(OH)2 and is used as a whitening material.

  1. Only P

  2. Only Q

  3. Only R

  4. P and Q

  5. Q and R
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

P. The central metal atom in potassium chromate and potassium dichromate is Cr. Chromium has +4 oxidation state in K2CrO4 and K2Cr2O7. Q. Limonite (Fe2O3.3H2O) is the ore of iron and willemite is the ore of zinc. R. Zinc oxide is an inorganic compound with the formula ZnO. ZnO is a white powder that is insoluble in water and it is widely used as an additive in numerous materials and products including rubbers, plastics, ceramics, glass, cement, etc. White lead (PbCO3)2•Pb(OH)2 is a complex chemical compound, containing both a carbonate and a hydroxide portion and occurs naturally as a mineral for lead. White lead compounds were used as pigmenting materials like cement, lubricants, etc, but due to its toxicity, it is not used frequently.

Hence, statements Q and R are incorrect.

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