Information by The University of Queensland and the COVID-19 clarification provided by the World Health Organisation (WHO) refutes the claim.
Some of the people have claimed that drinking various beverages would help kill the virus, but the virus does its work inside the cells. The University considered these claims as myths but not fact.
Similarly, WHO in the column of Fact or Fiction has mentioned about the misinformation regarding different kinds of remedies that were circulating in social media. It said that there is no evidence to prove that lemon, hot water, etc could kill the virus or cure a person with COVID-19.
The COVID-19 pandemic has given rise to a lot of potentially dangerous misinformation. For reliable advice on COVID-19 including symptoms, prevention and available treatment, please refer to the World Health Organisation or your national healthcare authority.