Chemical Reactions

Specific conductance (also called electrical conductivity) measures the ability of water to carry electric current. This ability depends on all charged species present in water, including: - cations (e.g., Ca²⁺, Mg²⁺, Na⁺)
- anions (e.g., Cl⁻, SO₄²⁻, HCO₃⁻)
Un-ionized species do not conduct electricity. Thus, conductivity accounts for total ionic strength, not one type of ion alone. Therefore, the correct statement is that specific conductance measures the presence of all ions. Final Answer: (B)

Step 1: Recall behavior of phenolphthalein.
Phenolphthalein turns pink in basic solutions (pH>8.3). If the solution remains colorless, it means OH ions are absent.
Step 2: Recall behavior of methyl orange.
Methyl orange turns yellow in basic solutions (pH>4.4). Since the solution turns yellow, the sample must be basic in nature, but not strongly alkaline.
Step 3: Link with carbonate/bicarbonate ions.
If phenolphthalein gives no color (absence of OH ), but methyl orange turns yellow (basicity present), then the alkalinity is due to CO or HCO . Thus, OH ions are absent, but carbonate/bicarbonate ions are present. Final Answer:

Step 1: Standard error of the mean (SEM).
For sample size ,
Step 2: Test statistic (Z).
Here , threshold = 6.
Step 3: Interpret Type I error.
Type I error = rejecting when is true. Since , Type I error occurs when . This corresponds to Final Answer:

Step 1: Understand the protonation states of phosphoric acid.
Phosphoric acid (H PO ) is a triprotic acid. It loses protons stepwise: The approximate pKa values for each step are: , , and .

Step 2: Analyze the speciation diagram based on pH.
Curve I: Dominates at low pH (pH < pKa ), so it represents fully protonated H PO .
Curve II: Peaks between pKa and pKa , representing H PO .
Curve III: Peaks between pKa and pKa , representing HPO .
Curve IV: Dominates at high pH (pH > pKa ), corresponding to PO .

Step 3: Match the curves with the chemical species.
I = H PO
II = H PO
III = HPO
IV = PO

Step 4: Compare with the given options.
Only option (3) matches the above assignments.

Step 1: Identify Diagram 'x'.
Diagram x shows a stirrer inside a closed container.
There is no inlet or outlet for flow.
This setup matches a Batch Reactor, where the contents are loaded, processed (with stirring), and then unloaded.
So, Diagram x corresponds to Batch Reactor (3).

Step 2: Identify Diagram 'y'.
Diagram y shows a tank with a stirrer, and has both inlet and outlet.
This is a classic representation of a Continuously Stirred Tank Reactor (CSTR).
In CSTR, reactants are continuously fed and products removed, while contents are stirred to maintain uniformity.
So, Diagram y corresponds to CSTR (2).

Step 3: Identify Diagram 'z'.
Diagram z shows a long cylindrical tube with inlet and outlet, and no stirrer.
This is the typical structure of a Plug Flow Reactor (PFR).
In a PFR, fluid flows in one direction through the pipe with no mixing in the flow direction.
So, Diagram z corresponds to Plug Flow Reactor (1).