In four of the following groups, the three

substances are either all strong electrolytes,
all weak electrolytes, or all nonelectrolytes.
Which group has one member which is NOT
like the others in the group?
1. BaCl2; NaNO3; HF
2. O2; CO(NH2)2; CH3OH
3. NaCl; Ca(OH)2; HNO3
4. NH3; CH3COOH; HCN
5. H2SO4; NaOH; HCl

are these is electrolytes in NaCl

To determine the group that has one member that is not like the others, we need to identify the substances as either strong electrolytes, weak electrolytes, or non-electrolytes.

An electrolyte is a substance that can conduct electricity when dissolved in water. Strong electrolytes dissociate completely into ions, while weak electrolytes only partially dissociate into ions. Non-electrolytes do not dissociate into ions and do not conduct electricity when dissolved in water.

Here's how you can analyze each group to determine the answer:

1. BaCl2; NaNO3; HF
- BaCl2 is a strong electrolyte because it dissociates completely into Ba²⁺ and Cl⁻ ions when dissolved in water.
- NaNO3 is also a strong electrolyte because it dissociates completely into Na⁺ and NO₃⁻ ions when dissolved in water.
- HF is a weak electrolyte because it only partially ionizes into H⁺ and F⁻ ions when dissolved in water.

In this group, HF is not like the others because it is a weak electrolyte, while the other two are strong electrolytes.

2. O2; CO(NH2)2; CH3OH
- O2 is a non-electrolyte because it does not dissociate into ions when dissolved in water.
- CO(NH2)2 (urea) is also a non-electrolyte because it does not ionize when dissolved in water.
- CH3OH (methanol) is a non-electrolyte because it does not dissociate into ions in water.

In this group, all three substances are non-electrolytes, so there is no member that is not like the others.

3. NaCl; Ca(OH)2; HNO3
- NaCl is a strong electrolyte because it dissociates completely into Na⁺ and Cl⁻ ions in water.
- Ca(OH)2 is also a strong electrolyte because it dissociates completely into Ca²⁺ and 2 OH⁻ ions in water.
- HNO3 is a strong electrolyte because it dissociates completely into H⁺ and NO₃⁻ ions in water.

In this group, all three substances are strong electrolytes, so there is no member that is not like the others.

4. NH3; CH3COOH; HCN
- NH3 (ammonia) is a weak electrolyte because it only partially ionizes into NH₄⁺ and OH⁻ ions in water.
- CH3COOH (acetic acid) is also a weak electrolyte because it only partially ionizes into H⁺ and CH3COO⁻ ions in water.
- HCN (hydrogen cyanide) is not an electrolyte because it does not dissociate into ions when dissolved in water.

In this group, HCN is not like the others because it is not an electrolyte, while the other two are weak electrolytes.

5. H2SO4; NaOH; HCl
- H2SO4 (sulfuric acid) is a strong electrolyte because it dissociates completely into 2 H⁺ and SO₄²⁻ ions in water.
- NaOH is also a strong electrolyte because it dissociates completely into Na⁺ and OH⁻ ions in water.
- HCl (hydrochloric acid) is a strong electrolyte because it dissociates completely into H⁺ and Cl⁻ ions in water.

In this group, all three substances are strong electrolytes, so there is no member that is not like the others.

Based on the analysis above, the group that has one member that is not like the others is group 4, which consists of NH3, CH3COOH, and HCN. HCN is not an electrolyte, unlike NH3 and CH3COOH.