Which of the following is correct for hydrogen?

Options

A. it can form bonds in `+1` as well as `-1` oxidation state.
B. it is collected at cathode
C. it has a very high ionisation potential
D. all of the above

Explanation

To determine which of the statements about hydrogen is correct, we will analyze each statement step by step.

### Step 1: Analyze the Oxidation States of Hydrogen
- Hydrogen can exhibit different oxidation states. It can have a +1 oxidation state in covalent compounds and a -1 oxidation state in ionic compounds.
- **Example of -1 oxidation state**: In sodium hydride (NaH), hydrogen has an oxidation state of -1.
- **Example of +1 oxidation state**: In hydrochloric acid (HCl) or hydrofluoric acid (HF), hydrogen has an oxidation state of +1.

### Step 2: Evaluate the Statement about Bond Formation
- The first statement claims that hydrogen can form bonds in both +1 and -1 oxidation states.
- Based on our analysis in Step 1, this statement is true.

### Step 3: Analyze the Statement about Hydrogen's Position in Electrolysis
- The second statement claims that hydrogen is collected at the cathode during electrolysis.
- In reality, hydrogen ions (H⁺) are reduced at the cathode to form hydrogen gas (H₂), while hydrogen in the form of hydride ions (H⁻) is oxidized at the anode to release H₂ gas and electrons.
- Therefore, this statement is false.

### Step 4: Evaluate the Ionization Potential of Hydrogen
- The third statement claims that hydrogen has a very high ionization potential.
- While hydrogen does have a relatively high ionization energy compared to many elements, it is not as high as that of noble gases. Thus, this statement is also false.

### Conclusion
- After analyzing all statements, we conclude that the first statement about hydrogen forming bonds in +1 and -1 oxidation states is correct.

### Final Answer
The correct statement for hydrogen is: **It can form bonds in +1 as well as -1 oxidation states.**

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