Rank the following 0.10 M solutions in order of increasing pH. (Use the appropriate <, =, or > symbol to separate substances in the list.)
HONH3NO3, HOBr, RbNO3, RbOH, HNO3, HONH2, RbOBr
HONH3NO3 (?)
HOBr (weak acid, so lower pH value but higher than bases)
RbNO3 (neutral, 7)
RbOH (?)
HNO3 (large Ka, so small pH value)
HONH2 (?)
RbOBr (salt, from Rb+ and OBr-)
I have:
HNO3 < HOBr < RbOBr < HONH3NO3 < RbNO3 < HONH2 < RbOH
I don't know the Ka values or the pH for some of them, so maybe someone can help me complete the ranking?
HONH2 is hydroxyl amine with Kb = 1.1
RbOH is a strong base so 0.1M gives 0.1M OH or pOH or 1 (pH of 13)
RbOBr is a salt so the pH is determined by the hydrolysis of OBr^-
OBr^- + H2O ==> HOBar + OH^- You can do an ICE chart on this and determine the pHknowing the Ka of HOBr. You can look that up on Google.
To complete the ranking, we need to consider the properties of the substances that affect pH. Here is the complete ranking in increasing order of pH:
1. HNO3 (strong acid, low pH due to complete ionization)
2. HOBr (weak acid, higher pH compared to strong acids)
3. RbOBr (salt, relatively neutral pH)
4. HONH3NO3 (weak acid, slightly higher pH than RbOBr)
5. RbNO3 (neutral salt, relatively neutral pH)
6. HONH2 (weak base, slightly higher pH than weak acids)
7. RbOH (strong base, higher pH due to complete ionization)
Complete ranking: HNO3 < HOBr < RbOBr < HONH3NO3 < RbNO3 < HONH2 < RbOH
To complete the ranking of the 0.10 M solutions in order of increasing pH, we can use some general knowledge about the properties of the substances in question.
First, let's consider the substances with known properties or information:
1. HNO3: Nitric acid (HNO3) is a strong acid, which means that it dissociates completely in water to produce H+ ions. Since it is a strong acid, it will have a low pH value. Thus, it should have the lowest pH among the given substances.
2. HOBr: Hypobromous acid (HOBr) is a weak acid. Although it is weaker than HNO3, it will still have a lower pH value compared to the neutral substances and bases. Therefore, it should have a pH value higher than HNO3 but lower than the remaining substances.
3. RbNO3: Rubidium nitrate (RbNO3) is a neutral salt. Since it does not produce any hydrogen ions or hydroxide ions when dissolved in water, it will have a pH value of around 7, which is considered neutral.
Now, let's analyze the remaining substances where we lack specific information:
4. RbOBr: Based on its formula, RbOBr is a salt composed of a metal cation (Rb+) and an anion (OBr-). Without specific information about its Ka value, we can assume that the pH of RbOBr would be close to neutral, similar to RbNO3.
5. HONH3NO3: This substance contains both acidic groups (H+) and basic groups (NH3). Without specific information about its properties, it is not possible to accurately determine its pH. However, considering that it contains an acidic group, it may have a slightly lower pH than RbOBr and RbNO3.
6. HONH2: Similarly to HONH3NO3, without specific information about its properties, it is difficult to accurately determine its pH. However, considering that it contains a basic group without an acidic counterpart, it may have a slightly higher pH than RbOBr and RbNO3.
7. RbOH: Rubidium hydroxide (RbOH) is a strong base, which means it dissociates completely in water to produce OH- ions. Since it is a strong base, it will have a high pH value. Therefore, it should have the highest pH among the given substances.
Based on this analysis, we can update the ranking as follows:
HNO3 < HOBr < RbOBr < HONH3NO3 < RbNO3 < HONH2 < RbOH
Please note that the ranking of HONH3NO3 and HONH2 may be interchangeable without detailed information about their properties.