The electronic configuration of two elements A and B are -
A first order reaction takes 20 minutes for 25% decomposition. Calculate the time when 75% of the reaction will be completed. Given: log 2= 0.3010 log 3= 0.4771 log 4=0.6021 (CBSE 2017)
Question: How many electrons flow through a metallic wire if a current of 0.5 A is passed for 2 hours? (Given: 1F= 96,500 C/mol) (CBSE 2017)
The value of current (I) 0.5 A and time (t) is given, so using the values in the formula
The cell in which the following reaction occurs:
2Fe3+(aq) + 2I-(aq)→ 2Fe2+(aq) + I2(s)
Question: Calculate the number of unit cells in 8.1 g of Aluminium if it crystallizes in a face cubic structure (fcc). (Atomic mass of Al = 27 g/mol) (CBSE 2017)
Solution: The weight of one mole of a substance is equal to its atomic mass in grams, therefore,
1 mole of Al = 27 g of Aluminium
Question- An organic compound X contains 70% Carbon, 11.33% Hydrogen and 18.67% Oxygen. The molecular weight of the compound is 86. It gives negative Tollens test but forms an addition product with sodium hydrogen sulfite. It also gives a positive iodoform test. On vigorous oxidation with KMnO4, the compound X decomposes to ethanoic acid and propanoic acid. What is the structure of compound X?
The oxidation number of Phosphorus (P) is the unknown here. Let us consider it as x.
The Oxidation Number of Hydrogen (H) is + 1
The Oxidation Number of Oxygen (O) is -2