Answer
The potential difference across C1 is different from previously.
Work Step by Step
Initially, the potential difference across C1 is equal to the battery voltage.
Then C2 is added in series.
When two capacitors are in series, the potential difference across each capacitor is different. The sum of potential difference across each capacitor will be equal to the total battery voltage.
Therefore, the potential difference across C1 is different from previously.
