You are presented with a white solid and told that due to careless labeling it is not clear if the substance is barium chloride, lead chloride, or zinc chloride. When you transfer the solid to a beaker and add water, the solid dissolves to give a clear solution. Next an Na2SO41aq2 solution is added and a white precipitate forms. What is the identity of the unknown white solid?
Ch.4 - Reactions in Aqueous Solution
4장, 문제 6
Which of the following ions will always be a spectator ion in a precipitation reaction? (a) Cl- (b) NO3- (c) NH4+ (d) S2- (e) SO42-
검증된 단계별 안내1
Identify the concept of a spectator ion: Spectator ions are ions that do not participate in the actual chemical reaction and remain unchanged in the solution.
Understand the context of a precipitation reaction: In a precipitation reaction, two soluble salts react to form an insoluble salt (precipitate) and other ions remain in solution.
Recall the solubility rules: Nitrate ions (NO3-) are always soluble in water, meaning they do not form precipitates with any common cations.
Analyze each option: Consider the solubility of compounds formed by each ion with common cations. Nitrate (NO3-) is known for forming soluble compounds with all cations.
Conclude which ion is always a spectator: Based on the solubility rules, NO3- is always a spectator ion in precipitation reactions because it does not form insoluble compounds.

비슷한 문제에 대한 검증된 영상 답변:
이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
주요 개념
질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.
Spectator Ions
Spectator ions are ions that do not participate in the actual chemical reaction during a precipitation reaction. They remain in the solution and do not change their oxidation state or form any precipitate. Identifying spectator ions is crucial for understanding the net ionic equation, which only includes the ions that undergo a change.
추천 영상:
가이드 코스
Ion Formation
Precipitation Reactions
Precipitation reactions occur when two soluble salts react in solution to form an insoluble compound, known as a precipitate. This process is driven by the formation of a solid that separates from the solution, and it is essential to recognize the solubility rules to predict which combinations of ions will lead to precipitation.
추천 영상:
가이드 코스
Selective Precipitation
Solubility Rules
Solubility rules are guidelines that help predict whether a compound will dissolve in water or form a precipitate. For example, most nitrates (NO3-) and ammonium (NH4+) salts are soluble, while sulfides (S2-) and carbonates (CO3^2-) are often insoluble. Understanding these rules is key to determining which ions will remain in solution and which will precipitate.
추천 영상:
가이드 코스
Solubility Rules
관련 실천
교과서 질문
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교과서 질문
Use the molecular representations shown here to classify each compound as a nonelectrolyte, a weak electrolyte, or a strong electrolyte (see Figure 4.6 for the element color scheme). (a)
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교과서 질문
The concept of chemical equilibrium is very important. Which one of the following statements is the most correct way to think about equilibrium? (a) If a system is at equilibrium, nothing is happening. (b) If a system is at equilibrium, the rate of the forward reaction is equal to the rate of the back reaction. (c) If a system is at equilibrium, the product concentration is changing over time.
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