All Students Notes

1. Which one of the following is the most basic? a) MgO b) BaO c) CaO d) SrO ... Answer is b) Explanation: Basic character of oxides of metals increases with increase in electropositive character (ability to loose the electron). Down the group, electropositive character of metal increases as atomic size or atomic radius increaeses due to increase in shells and decrease in effective nuclear charge due to increase in sheilding effect. As Ba is at bottom of these elements, therefore, Ba can loose valence electron easily and hence shows the most electropositive character. So, BaO is the most basic . show Answer 2. Which of the following oxides is amphoteric oxide? a) Na 2 O b) Al 2 O 3 c) MgO d) SO 2 ... Answer is b) Explanation: Amphoteric oxides are compounds which have ability to react as acid and base. Al 2 O 3 can act as an acid and base depending upon the conditions. Therefore, Al 2 O 3 is amphoteric....

1. Which of the following list contains only elements ? a) air, water, oxygen b) hydrogen, Oxygen, Brass c) air, water, Fire, Earth d) Calcium, Carbon, Sulphur ... Answer is d) Explanation: calcium, carbon and sulphur are only elements.In option a) air is an example of mixture and water is example of compound. In option b) brass is a mixture. In option c) air, fire and earth are examples of mixture and water is a compound. show Answer 2. The diagrams below represent particles in four substances, which box represents the particles of nitrogen a) b) c) d) ... Answer is d) Explanation: Particles of any pure substace are similar. Hence, diagram d contain similar diatomic molecules, so it represents particles of Nitrogen. show Answer 3. What is the formula mass of CuSO 4 ​​.5 H​​​​ 2 ​​O...