以下問題已知答案, 但不太明白, 求高人解釋
1. Which of the following oxides dissolves in both dilute sulphuric acid and sodium hydroxide solution?
A. CuO
B. MgO
C. Fe2O3
D. Al2O3
Ans: D
2. Which of the following reaction sequences is most suitable for preparing magnesium carbonate from magnesium in the laboratory?
A. Mg(s) + dil. HCl→MgCl2(aq) + Na2CO3(aq)→MgCO3(s)
B. Mg(s) + dil. H2SO4→MgSO4(aq) + CaCO3(s)→MgCO3(s)
C. Mg(s) + conc. HNO3→Mg(NO3)2(aq) + (NH4)2CO3(aq)→MgCO3(s)
D. Mg(s) + O2→MgO (s) + CO2 + H2O →MgCO3(s)
Ans: A
3. Silver nitrate + excess ammonia會出乜野?
係唔係silver hydroxide? 咁係咩色?
4. If a glass reagent bottle containing sodium hydroxide solution is allowed to stand in air for a few weeks, it is often difficult to remove the glass stopper due to the formation of a solid round the bottle neck. The solid is probably
A. Sodium oxide
B. Sodium peroxide
C. Sodium carbonate
D. Sodium hydrogencarbonate
Ans: C
THZ!!