Step 1: Analyze Statement I.
BCl\(_3\) is indeed covalent. It has a trigonal planar structure with electron-deficient boron, making it covalent.
Step 2: Analyze Statement II.
BCl\(_3\) undergoes hydrolysis, but the products are not [B(OH)\(_4\)]\(^{+}\) and BH\(_2^{+}\). Instead, it forms [B(OH)\(_3\)] and HCl, so Statement II is incorrect.
Step 3: Conclusion.
Statement I is correct, but Statement II is incorrect.
Final Answer:
\[
\boxed{\text{Statement I correct, Statement II incorrect}}.
\]