Chapter 13 in the 1891 version, chapter 11 in the 1890 version.
He stabbed him on his neck.
Henry to Basil.
The gossips about Dorian's depravity.
Basil visits Dorian to express his concern about Dorian's behavior at the opera. Basil is worried about the influence Lord Henry may be having on Dorian and wants to make sure Dorian is not being negatively influenced by him.
Dorian Gray appreciated Basil as a friend. Though Basil was attracted to Dorian Gray, there was nothing deep about it since he was only in love with Dorian Gray's appearance which gave a huge change on Basil's artistic skills. Dorian Gray appreciated their friendship. When Basil finally had the guts to tell him about his affections, Dorian was already a changed man. His mind was preoccupied with other thoughts like the mysterious painting, emptiness and guilt for all his evil deeds. He was bored of his conservative morality, and annoyed by his good advices.
Dorian kills basil because basil is the creator of dorians portrait which in turn allows dorian to live a life of evil but not reap the consequences of it physically. so when dorian sees basil before he goes to london, he is reminded of the all the mental pain he has put himself through.
He is (properly) afraid that Harry will corrupt Dorian.
On a party.
In "The Picture of Dorian Gray" by Oscar Wilde, Lord Henry, Dorian Gray, and Basil Hallward are present for lunch at Lord Henry's aunt's home. Lord Henry and Basil are discussing Dorian Gray, who is the subject of Basil's portrait.
He was afraid the picture shows his secret feelings for Dorian.
He tells him to pray together to regain his innocence.
Dorian has the innocence of ignorance, and is easily impressible. Basil has mature, stable morals, which resist even the almighty charms of Henry. Henry compared their looks: Basil's "rugged strong face and coal-black hair" and Dorian, who looks like he was "made of ivory and rose petals".