SINGAPORE – An error in the A-level chemistry exam on Wednesday morning was dealt with differently across schools, resulting in students finishing the exam at different times.

In response, the Singapore Examinations and Assessment Board (SEAB) will work with Cambridge University - which assesses the A levels - to ensure that students are fairly assessed following the incident, it said.

It will also review how errata, or corrections, are managed to avoid such incidents in future, it said in response to queries by The Straits Times.

A question in the third paper of the H2 Chemistry exam showed a bond between two elements drawn incorrectly in one of the diagrams.

The error involved two sub-parts of an optional question. They were worth one mark each.

SEAB issued a note which clarified the structural representation of organic molecules in prose together with the question paper to every student at the start of the examination, it said.

SEAB added that a few schools sought further clarifications on the error note in the midst of the exam.

SEAB issued these by sharing a diagram. Schools were asked to announce the clarifications on the error note to their students where they deemed necessary, SEAB said.

They were were also advised to give make-up time to account for the duration of the announcement, it said.

Three students who spoke to ST but asked not to be identified said candidates at some schools were given extra time to make up for the time spent by invigilators explaining the error, while at other schools, they were not.

ST understands that at Nanyang Junior College, an errata slip was circulated to students before the paper began. The slip pointed out that atomic bonds had been drawn wrongly in three chemical structures.

The exam, which was scheduled for two hours between 8am and 10am, ended at 10.06am as the students were given an extra five minutes to check their papers.

However, at Hwa Chong Institution, students were not given extra time. An errata paper was given to them with their papers before the exam started for them to read, and the exam took place as planned, from 8am to 10am.

The error and the differences in how schools dealt with it was discussed on the website Reddit.

Some posters said it was unfair to students who did not get extra time. Some said the disruption caused by the error affected their focus.

The error was in Question 5, an optional question, so students could have chosen to do another one instead.