The strong basis - the inorganic chemical compound formed by hydroxyl group - IT and alkaline (elements I of group of a periodic system: Li, K, Na, RB, Cs) or alkaline-earth metal (elements II of the Ba, Ca group). Register in the form of formulas of LiOH, KOH, NaOH, RbOH, CsOH, Sa (IT) ₂, Wa (IT) ₂.
It is required to you
- vyparitelny cup
- torch
- indicators
- metal core
- NRO ₄
Instruction
1. The strong bases show the chemical properties characteristic of all hydroxides. Availability of alkalis in solution is determined by change of coloring of the indicator. With the studied solution add methyl orange, phenolphthalein to test or lower a litmus piece of paper. Methyl orange gives yellow coloring, phenolphthalein – purple, and litmus paper is painted in blue color. The basis is stronger, the indicator is painted more intensively.
2. If you need to learn what alkalis are presented, then carry out the qualitative analysis of solutions. The most widespread strong bases are hydroxides of lithium, potassium, sodium, barium and calcium. The bases react with acids (neutralization reactions) with formation of salt and water. At the same time it is possible to allocate Sa (IT) ₂, Wa (IT) ₂ and LiOH. In interaction with orthophosphoric acid insoluble precipitation is formed. Other hydroxides will not leave a sediment since all salts K and Na are soluble. (IT) ₂ + 2 NRO ₄ - → Ca ₃ (PO ₄) ₂↓ + 6 HO3 of Wa (IT) ₂ +2 NRO ₄ - → Wa ₃ (PO ₄) ₂↓ + 6 HO3 LiOH + NRO ₄ - → LiPO ₄↓ + 3 NOProtsedite them also dry up 3 Sa. Bring the dried-up precipitation in a torch flame. It is possible to determine by change of coloring of a flame qualitatively ions of lithium, calcium and barium. Respectively you define where what hydroxide. Salts of lithium paint a torch flame in carminic-red color. Barium salts – in green, and calcium salts – in crimson.
3. The remained alkalis form soluble ortho-phosphates.3 NaOH + NRO ₄ - → NaPO ₄ + 3 HO3 KOH + NRO ₄ - → KRO ₄ + 3 NONeobhodimo to evaporate water till the dry rest. Serially bring the evaporated salts on a metal core in a torch flame. Where there is a sodium salt – the flame will be painted in bright yellow color, and potassium ortho-phosphate – in pink-violet. Thus having the minimum set of the equipment and reactants you defined all strong grounds given to you.